September 2024 – Page 31 – Jharkhand Board Solution

JAC Class 9 Science Notes Chapter 9 Force and Laws of Motion

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 9 Notes Force and Laws of Motion

→ Force: It is a push or pull on an object that produces acceleration in the body on which it acts. The SI unit of force is ‘newton’. Forces are used in our daily life actions like pushing, lifting, pulling, stretching, twisting and pressing.

→ A force cannot be seen. It can be judged only by the effects which it can produce in several bodies (or objects) around us.

→ Force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newton and represented by the symbol ‘F’

→ Effects of Force:
a. Force can set a stationary body in motion. For example, a football can be set in motion by kicking it, i.e. by applying a force.

b. Force can stop a moving body. For example, by applying brakes, a running cycle or a running vehicle can be stopped.

c. Force can change the direction of a moving object. For example, by applying force, i.e., by moving handle, the direction of a running bicycle can be changed. Similarly by moving steering, the direction of a running vehicle is changed.

d. Force can change the speed of a moving body. For example, by accelerating, the speed of a running vehicle can be increased or by applying breaks, the speed of a running vehicle can be decreased.

e. Force can change the shape and size of an object. For example, by hammering, a block of metal can be turned into a thin sheet. Also by hammering, a stone can be broken down into pieces.

→ Balanced forces: If the resultant force of several forces acting on a body is zero, the forces are said to be ‘balanced forces’.

→ Unbalanced forces: If the resultant force of the several forces acting on a body is not zero, the forces are said to be ‘unbalanced forces’. An object in rest can be moved by applying unbalanced forces. Only an unbalanced force can produce the effects of force.

→ Newton’s First Law of Motion: An object remains in its state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.

→ Inertia: The natural tendency of an object to resist a change in its state of rest or of uniform motion is called its inertia.

Inertia of rest: It is the tendency of a body to remain in its state of rest.
Inertia of motion: It is the tendency of a body to remain in its state of uniform motion in a straight line.
Inertia of direction: It is the inability of a body to change, by itself, its direction of motion.

→ Newton’s Second Law of Motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force.
Mathematically,
Force = Mass × Acceleration or,
F ∝ \(\frac{P_{1}-P_{2}}{t}\) or \(\frac{\mathrm{m}(\mathrm{v}-\mathrm{u})}{\mathrm{t}}\) or ma
This law defines the unit of force. One unit force is that force which produces unit acceleration in a body of unit mass.

→ Newton (N): It is the SI unit of force. One Newton is that force which produces an acceleration of lm/s2 in a body of mass 1 kg.

→ 1 newton = 1 kg × 1 m/s² or 1N = 1 kg m/s²

→ Momentum: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. Its SI unit is kg m/s.
Momentum = Mass × Velocity or p = mv

→ Newton’s Third Law of Motion: To every action, there is an equal and opposite reaction and they act on two different bodies.

→ Law of Conservation of Momentum:
It states that the total momentum of any system of objects remains constant in the absence of any external force. According to the law of conservation of momentum, for collision between two bodies:
Total momentum before collision = Total momentum after collision
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

→ Frictional force: Whenever a body slides or rolls over the surface of another body, a force comes into action which acts in the opposite direction as that of the motion of a body. This opposing force is called ‘friction’.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 8 Motion

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 8 Notes Motion

→ An object is said to be in motion if it changes its position with the passage of time with respect to a fixed point in the background.

→ Types of Motion
a. Linear motion: A body is in linear motion if it moves in a straight line or path.
b. Circular motion (rotational): A body is in circular motion if it moves around a fixed point. A vertical line passing through the fixed point around which the body moves is known as axis of rotation.
c. Vibratory motion: A body has vibratory motion if it moves to and fro about a fixed point.

→ Concept of a Point object, Rest and Motion a. Point object: An extended object can be treated as a point object when the distance travelled by the object is much greater than its own size.
“A point object is one, which has no linear dimensions but possesses mass”.
b. Rest: A body is said to be at rest when its position does not change with time with respect to the observer.
c. Motion: A body is said to be in motion when its position changes with time with respect to the observer.

→ Vector and Scalar Quantities
a. Vector Quantities: The physical quantities that have magnitude as well as direction are called vector quantities.
Examples: Velocity, acceleration, force, displacement, momentum, weight, electric field, etc.

b. Scalar Quantities: The quantities that have only magnitude and no direction are called scalar quantities.
Examples: Mass, time, distance, speed, work, power, energy, charge, area, volume, density, pressure, potential, temperature, etc.

→ Distance and Displacement
a. Distance: It is the actual path travelled by an object from its initial position to its final position.
b. Displacement: It is the shortest straight line path between initial and final positions.
– If the initial and final points are same, displacement will be zero.
– Distance depends on path but displacement does not.
– Distance is always greater than or equal to displacement. They are equal only in straight line motion in a definite direction.
JAC Class 9 Science Notes Chapter 8 Motion 1

→ Uniform and Non-uniform Motion
a. Uniform motion is a motion in which equal distances are covered in equal time intervals.
b. Non-uniform motion is a motion in which unequal distances are covered in equal intervals of time.

→ Speed and Velocity
a. Speed: Speed is the distance travelled by an object in unit time.
Speed = \(\frac{\text { Distance travelled }}{\text { Time taken }}\)
or v = \(\frac{\mathrm{s}}{\mathrm{t}}\)
[where v = speed; s = distance; and t = time taken]
The SI unit of speed is m/s.

→ Average speed: It is the total distance travelled by the body divided by the total time taken to cover this distance.
Average speed = \(\frac{\text { Total distance travelled }}{\text { Total time taken }}\)

→ Uniform speed: When an object covers equal distances in equal intervals of time, however small these intervals may be, it is said to be in ‘uniform speed’.

→ Non-uniform speed: When an object covers unequal distances in equal intervals of time, it is said to be in ‘non-uniform speed’.

b. Velocity: It is the displacement of the body per unit of time. It is the distance travelled by a body per unit time in a given direction.
Velocity = \(\frac{\text { Displacement }}{\text { Time }}\)
The SI unit of velocity is m/s.

→ Important note: Velocity has both magnitude and direction while speed has only magnitude and no direction. Velocity has same direction as that of displacement.

→ Average velocity: The ratio of total displacement to the total time taken by the body gives its average velocity.
Average velocity = \(\frac{\text { Total displacement }}{\text { Total time taken }}\)

Average speed is always greater than average velocity, except in case of straight line motion without U – turn, when both are equal.
If body returns to its initial position, average velocity will be zero but average speed-will not be zero.
When direction of motion changes, velocity also changes.

→ Instantaneous Speed and Velocity
a. Instantaneous speed: It is the speed of an object at a particular moment (instant) in time.
b. Instantaneous velocity: It is the velocity of an object in motion at a specific point in time.

→ Acceleration: Acceleration is the measure of change of velocity with time. It is also called rate of change of velocity. The SI unit of acceleration is m/s2. It is a vector quantity.
Acceleration = \(\frac{\text { Final velocity – Initial velocity }}{\text { Total time taken }}\)
If the velocity of an object changes from an initial value ‘u’ to the final value ‘v’ in time ‘f, the motion is called accelerated motion. In this case, acceleration ‘a’ is given by
a = \(\frac{\mathrm{v}-\mathrm{u}}{\mathrm{t}}\)

Accelerated motion is a motion in which acceleration is not equal to zero.
a. Acceleration has same direction as that of velocity, if velocity increases.
b. Acceleration has opposite direction as that of velocity, if velocity decreases. In this case, acceleration will be negative. Negative acceleration is also called retardation or deceleration.

→ Uniform and Non-uniform Acceleration
a. When velocity of a body changes by equal amounts in equal time intervals, acceleration is said to be uniform.
b. When velocity of body changes by unequal amounts in equal intervals of time, acceleration is said to be non-uniform.
Examples: A freely falling ball is under uniformly accelerated motion. A car driving by applying brakes frequently, is under non-uniformly accelerated motion.

→ Equations of Uniformly Accelerated Motion:
Relation among velocity, distance, time and acceleration gives the equation of motion. There are three equations of motion for bodies moving with uniform acceleration.
a. First Equation of Motion: v = u + at

b. Second Equation of Motion:
s = ut + \(\frac{1}{2}\) at²

c. Third Equation of Motion:
v² = u² + 2as
Here,
v = final velocity of the body
u = initial velocity of the body
a = acceleration of the body
t = time taken by the body
s = distance travelled by the body in time ‘t’

→ Average velocity in Uniformly Accelerated Motion: If a body moves a distance ‘s’ in time ‘t’
Average velocity = \(\frac{\text { Displacement }}{\text { Time }}=\frac{\mathrm{s}}{\mathrm{t}}\)
= u + \(\frac{1}{2}\)at (∵ s = ut + \(\frac{1}{2}\)at²)
or, u + \(\frac{1}{2}\)at = u + \(\frac{1}{2}\)(u – v) (∵ v = u + at)
= u + \(\frac{\mathrm{v}}{2}-\frac{\mathrm{u}}{2}=\frac{\mathrm{u}+\mathrm{v}}{2}\)
Here, ‘a’ is uniform acceleration of body.
Average velocity = \(\frac{u+v}{2}\)

→ Graphical Representation of Motion: To describe the motion of an object, we can use different graphs. Graphical representation of motion shows dependence of one physical quantity, such as distance or velocity, on another quantity such as time.
a. Distance-time Graph: The change in the position of an object with time can be represented on the distance-time graph. The s-t graph for a moving body can be used to calculate the speed of the body.
JAC Class 9 Science Notes Chapter 8 Motion 2

b. Velocity-time Graph
– If a body moves with a uniform velocity (no acceleration), its speed-time graph would be a straight line parallel to time axis.
If a body moves with a non-uniform velocity (uniform acceleration), its speed time graph would be a straight line. If velocity increases (positive uniform acceleration) with time, graph would be a straight upward slope. If velocity decreases (negative uniform acceleration) with time, graph would be a straight downward slope.
JAC Class 9 Science Notes Chapter 8 Motion 3
We can find out the magnitude of displacement (distance) and acceleration of a body using the velocity-time graph. The distance travelled by a moving body in a given time will be equal to the area under the speed-time graph.

→ Velocity-time graph of an object moving with constant velocity
For the above graph,
Distance travelled = area of rectangle ABCD = AB × BD
s = v(t₂ – t₁)
Acceleration of body = \(\frac{\text { Change in velocity }}{\text { Time taken }}\)
As in above graph, velocity is constant, so in this case, acceleration will be zero.

→ Derivation of equation of motion using graphs:
Let an object move from A to B in time interval ‘f.
Acceleration of moving object = \(\frac{v_{2}-v_{1}}{t_{2}-t_{1}}\)
a. If initial velocity is u and final velocity is v then
a = \(\frac{v-u}{t-0}\)
at = v – u
v = u + at …(1)
Hence proved
JAC Class 9 Science Notes Chapter 8 Motion 5

b. Distance travelled by object = area under graph
= area of rec. ADCO + area of triangle ABD
= (AO) (OC) + \(\frac{1}{2}\) (AD) (DB)
= ut + \(\frac{1}{2}\) (OC) (BC – CD)
= ut + \(\frac{1}{2}\) t (v – u)
= ut + \(\frac{1}{2}\) t (at)
or
s = ut + \(\frac{1}{2}\)at² ….(2)

c. Distance travelled by object = area under graph
= area of trapezium AOCB
s = \(\frac{1}{2}\) (sum of ∥ sides) × t
S = \(\frac{1}{2}\) (u + v) × t …(i)
From first equation of motion, (v-u)
t = \(\frac{(v-u)}{a}\)
Equating equations (i) and (ii)
s = \(\frac{(v+u)(v-u)}{2 a}\) ……..(iii)
Hence proved

→ Circular Motion
a. Uniform circular motion is the motion in which an object moves on a circular path with constant speed. For example: moon revolving around the earth.
b. Non-uniform circular motion is the motion in which an object moves on circular path with varying speed. When an object is in circular motion, direction of its velocity keeps on changing.

→ Speed in the case of circular motion
Suppose a body is moving in a circular path of radius r.
Speed (v) = \(\frac{\text { Distance }}{\text { Time }}\)
= \(\frac{\text { Circumference of circle }}{\text { Time }}\)
= \(\frac{2 \pi r}{t}\)
JAC Class 9 Science Notes Chapter 8 Motion 6

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 7 Notes Diversity in Living Organisms

→ Biodiversity: The word ‘biodiversity’ is used to define the diversity of life forms. Biodiversity is a word more often used to refer to the variety of life forms found in a particular geographic region.

→ Diversity: Diversity of life forms in a geographic region provides stability in that region.

→ Taxonomy: It is a branch of biology . which deals with identification, nomenclature and classification of organisms. Carolus Linnaeus is called the father of taxonomy.

→ Classification: The method of arranging organisms into groups or sets on the basis of similarities and differences is called classification.

→ Importance of Classification
a. It makes the study of a wide variety of organisms easy and systematic.
b. It helps to understand how the different organisms have evolved with time.
c. It helps to understand the inter-relationships among different groups of organisms.
d. It forms a base for the study of other biological sciences, like biogeography.

→ Classification of organisms by Aristotle: Greek philosopher, Aristotle first classified the animals based on their place of residence, i.e., whether they lived on land, in water or in the air. However, this was not an appropriate way to group organisms as animals living in the same habitat can have very different characteristics.

→ Later, all the living organisms were identified and categorised on the basis of their body structure and function. The idea of evolution was first described by Charles Darwin in 1859 in his book ‘The Origin of Species.’

→ Basis of Classification: There are certain features or properties used for the classification of living organisms which are known as characteristics. Organisms with same characteristics are placed in same groups.

→ The major characteristics considered for classification of all organisms into five major kingdoms are:
a. Type of cellular organisation
i. Prokaryotes: The organisms which have cells without well defined nucleus are called prokaryotes.
ii. Eukaryotes: The organisms which have cells with well defined nucleus are called eukaryotes. Presence of nucleus and membrane bound organelles give better efficiency to the cells.

b. Body organisations
i. Unicellular: The organisms made up of a single cell alone are termed as unicellular organisms. In them, the single cell is responsible for carrying out all the necessary functions to maintain life.
ii. Multicellular: The organisms made up of more than one cell are called multicellular organisms. Because of more number of cells, there can be some division of labour to gain more efficiency.

c. Mode of obtaining food
i. Autotrophs: Organisms producing their own food are called autotrophs. All green plants are examples of autotrophs. They have a pigment called chlorophyll, which facilitates photosynthesis.
ii. Heterotrophs: Organisms who are dependent on either plants or animals are called heterotrophs. They do not have chlorophyll. All animals, fimgi, various bacteria and protozoa belong to this group.

→ Hierarchy of Classification:
Linnaeus proposed a classification system that arranged organisms into taxonomic groups at different levels according to the characteristics they have. The groups or the levels from top to bottom are:
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 1

→ Nomenclature: An organism can have different names in different languages. This creates confusion in naming the organism. So, a scientific name is needed which is accepted globally. Binomial system of nomenclature given by Carolus Linnaeus is used for naming different organisms.

→ Following are some conventions in writing the scientific names:
a. Genus should be written first, followed by the name of the species.
b. First letter of the genus should be capital and that of the species should be in small letter.
c. When printed, the name should be written in italics and if hand written, the genus and the species should be underlined separately.
For example – Homo sapien for human, Panthera tigris for tiger.

→ Classification System
a. Two Kingdom Classification: Carolus Linnaeus in 1758 classified the living organisms into two groups, viz., plants and animals.
b. Five Kingdom Classification: Whittaker in 1959, further classified the organisms into five kingdoms,viz. Monera, Protista, Fungi, Plantae and Animalia.

→ Carl Woese in 1977 further divided kingdom Monera into Archaebacteria (or Archaea) and Eubacteria (or Bacteria).

→ Kingdom Monera
a. Prokaryotic, unicellular.
b. Can be autotrophic or heterotrophic.
c. May or may not have a cell wall.
d. Examples: Anabaena and bacteria (heterotrophic), Cyanobacteria or blue green algae (autotrophic).
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 3

→ Kingdom Protista
a. Eukaryotic, unicellular.
b. Can be autotrophic or heterotrophic.
c. Have cilia, flagella or pseudopodia for locomotion.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 4
d. Examples: Plant like – unicellular algae, diatoms; Animal like – protozoans (Amoeba, Paramecium, Euglena); Fungi like – slime moulds and water moulds.

→ Kingdom Fungi
a. Heterotrophic, eukaryotic organisms.
b. Saprophytic. They use.decaying organic materials as food.
c. Some fungi live in a symbiotic relationship with cyanobacteria. They are called lichens. The algal part provides food and the fungal part provides minerals and substratum.
d. Cell wall is made up of chitin.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 5
e. Examples: Mushrooms (Agaricus), green mould (Penicillium), smut (Aspergillus).

→ Kingdom Plantae:
a. Multicellular, eukaryotic.
b. Autotrophs, use chlorophyll for photosynthesis.
c. Cellulosic cell wall present.

→ Kingdom Animalia:
a. The organisms of Animalia include all organisms which are multicellular, eukaryotic and without cell wall.
b. Organisms of kingdom Animalia are heterotrophs.

→ Classification of Kingdom Plantae
Based upon body differentiation, types of vascular tissues (xylem or phloem), reproductive structures (seeds or spores) and type of seeds, (covered or naked), kingdom plantae is divided into the following divisions:

→ Division 1: Thallophyta
a. The plants of thallophyta do not have well differentiated body.
b. The plants in thallophyta are known as algae and they are predominantly aquatic.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 6
c. Examples: Spirogyra, Ulothrix, Cladophora, Chara, etc.

→ Division 2: Bryophyta
a. The plants of this group are called amphibians of plant kingdom.
b. Though not distinctly developed, plant body can be differentiated to form stem and leaf like-structures.
c. Examples: Moss (Funaria) and Marchantia.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 7

→ Division 3: Pteridophyta
a. Plants of Pteridophyta have defined roots, stems and leaves.
b. These plants have specialised tissues that transport water and other materials from one part to another part of the plant.
c. Examples: Marsilea, fem and horse-tails.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 8
d. The similarity among the thallophytes, the bryophytes and the pteridophytes is that all of them have naked embryos, which are known as spores.
e. The plants of these groups are known as ‘cryptogams’, which means ‘hidden reproductive organs’.

→ Division 4: Gymnosperms
a. The plants of this group bear naked seeds and are usually perennial, evergreen and woody.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 9
b. Examples: Pine, Cycas and Deodar.

→ Division 5: Angiosperms
a. This word is made from two Greek words: angio- meaning covered and sperma- meaning seed.
b. The seeds develop inside an organ which is modified to become a fruit. These are also called flowering plants.
c. Plant embryo in seeds has structures called cotyledons. Cotyledons are called ‘seed leaves’ because in many instances they emerge out and become green when the seed germinates.
d. The angiosperms are divided into two groups on the basis of the number of cotyledons present in the seed:

Monocots (Monocotyledonous): These seeds have a single cotyledon. E.g., onion.
Dicot (Dicotyledonous): These seeds have two cotyledons. E.g., musturd.

JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 10

→ Classification of Kingdom Animalia
Based on the extent and type of the body design differentiation, Animal kingdom is classified into the following phyla:

→ Phylum Porifera
a. Cellular level of organisation.
b. Non-motile animals.
c. Holes on the entire body surface which lead to a canal system for circulation of water and food.
d. Hard outside layer known as skeleton.
e. Examples: Sponges (Spongilla, Sycon).
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 11

→ Phylum Coelenterata
a. Tissue level of organisation.
b. No coelom.
c. Radial symmetry’, diploblastic.
d. Hollow gut, move from one place to another.
e. Examples: Hydra, sea-anemone, jelly fish, corals.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 12

→ Phylum Platyhelminthes
a. Well-developed organs.
b. No coelom.
c. Known as flatworms.
d. Bilateral symmetry, triploblastic.
e. Free living or parasitic.
f. Digestive cavity has a single opening for ingestion and egestion.
g. Examples: Planaria, liverfluke, tape worm, etc.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 13

→ Phylum Nematoda
a. Cylindrical body.
b. No well-developed body (i.e., no real organ).
c. False coelom.
d. Bilateral symmetry, triploblastic.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 14
e. Many are parasitic worms living inside human body and can cause various diseases, like filarial worms cause elephantiasis, round worms and pin worms living in human intestine cause infection.
f. Examples: Ascaris, Wuchereria.

→ Phylum Annelida
a. Found everywhere including fresh water, marine water as well as on land.
b. Bilaterally symmetrical and triploblastic body.
c. True body cavity present.
d. Segmented (segments specialised for different functions).
e. Extensive organ differentiation.
f. Examples: Earthworm, Nereis, leeches.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 15

→ Phylum Arthropoda
a. The largest group of animals.
b. Open circulatory system.
c. Generally known as insects.
d. Bilateral, triploblastic.
e. Segmented, sometimes fused.
f. Jointed appendages like feet, antenna.
g. Examples: Prawns, butterflies, houseflies, spiders, scorpions, etc.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 16

→ Phylum Mollusca
a. Coelom present.
b. Triploblastic, bilateral symmetry.
c. Soft bodies, sometimes covered with shell.
d. Generally not segmented.
e. No appendages present.
f. Kidney-like organs for excretion.
g. Examples: Chiton, Octopus, Pila, Unio.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 17

→ Phylum Echinodermata
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 18
a. Spiny skinned.
b. Free-living marine organisms.
c. Triploblastic with coelom present.
d. Skeleton of calcium carbonate.
e. Water vascular system for locomotion.
f. Bilateral symmetry before birth.
g. Examples: Starfish, sea cucumber,
feather star, etc.

→ Phylum Hemichordata
a. Small group of marine animals.
b. Cylindrical, bilateral symmetry, triploblastic.
c. Coelom present.
d. Gills for respiration.
e. Examples: Balanoglossus.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 19

→ Phylum Chordata
a. Bilateral symmetry, triploblastic.
b. Coelom present.
c. Notochord present.
d. Gills presented at some phase of life.
e. Dorsal nerve chord.
f. Post-anal tail present at some stage of life, e.g., in human beings during embryonic stages.

Phylum chordata is further subdivided into three sub-phyla, namely, urochordata, cephalochordata and vertebrata. Urochordata and cephalochordata are together called as Protochordata.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 20
a. Protochordata

Bilaterally symmetrical, triploblastic.
Coelom present.
Marine.
Examples: Herdmania, Amphioxus,

JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 21

b. Vertebrata

Notochord is replaced by vertebral column
Two, three, four chambered heart. Examples: Human (4 chambered), frog (3 chambered), fishes (2 chambered).
Organ for excretion, e.g., kidney, is present.
Paired appendages.

→ Classification of Vertebrata
The organisms of this kingdom have a true vertebral column and an internal skeletal structure. Vertebrates are further classified into the following classes:

Cyclostomata:
a. Jawless vertebrates.
b. Elongated body.
c. Circular mouth, slimy skin, scaleless.
d. Ectoparasites or borers of other vorebebrates.
e. Example: Petromyzon, Myxine (Hagfish).
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 22

Pisces:
a. The organisms of this group are typically different types of fishes.
b. Fishes can live only in water.
c. The skin of fishes is covered with scales/plates.
d. Fishes use oxygen dissolved in water to breathe with the help of the gills.
e. The tail of a fish helps in its movements.
f. Fishes are cold-blooded organisms and their hearts have only two chambers.
g. Fishes lay eggs (oviparous).
h. Examples: Rohu, Catla, Scoliodon, etc.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 23

Amphibia:
a. The organisms of Amphibia have mucus glands in the skin, and they have three- chambered heart.
b. Amphibians can live in water as well as on land.
c. These organisms respire through either gills or lungs.
d. They lay eggs.
e. Examples: Salamander, toad, frog, etc.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 24

Reptilia:
a. The organisms of Reptilia are cold blooded. They cannot maintain a constant body temperature.
b. They have three-chambered heart, except crocodiles which have four- chambered heart.
c. These organisms lay eggs with tough coverings (oviparous).
d. They have scales.
e. Examples: King cobra, turtle, chameleon, lizard, etc.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 25

Aves:
a. Aves are warm-blooded.
b. These organisms lay eggs.
c. Most of the Aves have feathers.
d. Four-chambered heart is present.
e. They have hollow bones which help them to fly.
f. Examples: Pigeon, crow, etc.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 26

Mammalia
a. The organisms of Mammalia are warmblooded and they have four-chambered heart.
b. Mammalia are typically characterised for their mammary glands.
JAC Class 9 Science Notes Chapter 7 Diversity in Living Organisms 27
c. Mammary glands produce milk to nourish the young ones.
d. Most of the mammals give birth to young ones. However, a few mammals, such as the Platypus and the Echidna, lay eggs.
e. Skin of mammals has hair along with sweat and oil glands.
f. Examples: Human, bat, cat, whale, etc.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 6 Tissues

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 6 Notes Tissues

→ A group of cells having a common origin and similar function are termed as tissues.

→ Plant tissues: They are primarily classified into two groups:
a. Meristematic tissues
b. Permanent tissues

Meristematic tissues: They are capable of dividing continuously to produce new cells. The meristematic tissues are present only at the growing regions such as shoot tip. root tip and at the base of intemodes and leaves.
JAC Class 9 Science Notes Chapter 6 Tissues 1
Depending on the area where they are present, meristematic tissues are classified as apical, lateral and intercalary. Meristematic tissues are very active, have dense cytoplasm, thin cellulosic walls and prominent nuclei. They lack vacuoles.

Permanent tissues: Formed from meristematic tissues, the cells in the tissue lose the ability to divide. They have differentiated and attained a permanent shape suitable for their functions. Permanent tissues are divided into two categories. Simple permanent tissues: Tissues which are made up of only one type of cells are called simple tissues.

Parenchyma, collenchyma and sclerenchyma are examples of simple tissues,
a. Parenchyma: Composed of unspecialised cells with relatively thin cell walls, large intercellular space, present in soft parts of the plant. Their main function is storage.
JAC Class 9 Science Notes Chapter 6 Tissues 2

b. Collenchyma: It is composed of living and elongated cells with cell walls and irregularly thickened at the comers. There is very little intercellular space. It provides mechanical support and elasticity to plant. It helps in bending of leaves and stems.

c. Sclerenchyma: It is composed of long, narrow and thick-walled cells. This tissue is made up of dead cells, and there are no intercellular spaces. Sclerenchyma cells are dead. They are present in seeds, nuts, husk of coconut- fibre of jute, etc.
JAC Class 9 Science Notes Chapter 6 Tissues 3

→ Complex permanent tissues: Made up of more than one type of cells (conducting tissues).
a. Xylem: It is composed of tracheids, vessels, xylem parenchyma and xylem fibres. Xylem conducts water and dissolves minerals from roots to all parts of the plant. Except xylem parenchyma, xylem cells are dead cells.
JAC Class 9 Science Notes Chapter 6 Tissues 4
b. Phloem: It conducts food from the green leaves/parts to other parts of the plant. It is composed of four elements-sieve tubes, companion cells, phloem parenchyma and phloem fibres. Except phloem fibres, phloem cells are living cells.

→ Animal tissues: Animal tissues are of four types in higher animals including human beings.
JAC Class 9 Science Notes Chapter 6 Tissues 6
a. Epithelial tissues: They are present for the covering of the external surfaces, internal cavities and organs of the animal body. Various types of epithelial tissues are:

Squamous epithelium in the lining of mouth and oesophagus.
Cuboidal epithelium in the lining of kidney tubules and salivary glands.
Columnar epithelium in the intestine and columnar epithelium with cilia in the lining of respiratory tract.
Glandular epithelium in the glands aids in a special function as gland cells, which can secrete at the epithelial surface.

b. Muscular tissues: They are made up of muscle cells, called muscle fibres. There are three types of muscle fibres:

Striated muscles (skeletal muscles or voluntary muscles): Cells are cylindrical, unbranched and multinucleate.
Smooth muscles (involuntary muscles): Cells are long, spindle-shaped and possess a single nucleus.
Cardiac muscles (involuntary muscles): Cells are cylindrical, branched and uninucleate.

c. Connective tissues: They connect various tissues and organs. They provide support to different parts of the body by forming packaging around different organs of the body. The different types of connective tissues in our body are bone, cartilage, tendon, ligament and blood.

d. Nervous tissues: The tissue responds to stimuli. The brain, spinal cord and nerves are composed of nervous tissues or neurons. A neuron consists of cell body, cytoplasm, nucleus, dendrite, axon and nerve ending. The neuron impulse allows us to move our muscles when we want to respond to stimuli.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 5 Notes The Fundamental Unit of Life

→ All organisms consist of tiny building blocks which are known as cells. The term ‘cell’ was coined by Robert Hooke from the Latin word ‘cella’ which means a Tittle room’.

→ Cell is the basic structural and functional unit of all organisms. Cell is the lowest level of organisation that is ‘alive’.

→ Cell theory states that: All living organisms are composed of cells. Cell is the fundamental unit of life. All new cells arise from pre-existing cells.

→ Shape and size of cells: Cells vary in shape and size. They may be oval, spherical, rectangular, spindle shaped or totally irregular like the nerve cell. The size of cells also varies in different animals and plants. Most of the cells are very small in size, like red blood cells (RBCs), while some cells are fairly large, like nerve cells. Average size of a cell varies from 0.5 to 20 pm.

→ Cell Structure: Cell is a compound of same basic constituents.
1. Plasma membrane: Plasma membrane is the covering of the cell that separates the contents of the cell from its external environment. It is the living part of a cell. It is a very thin, delicate, elastic and selectively permeable membrane. As it is a selectively permeable membrane, it allows the flow of certain selected substances in and out of the cell. The plasma membrane is flexible and is made up of organic molecules called lipids and proteins. The flexibility of cell membrane also enables the cell to engulf food and other materials from its external environment. Such process is known as endocytosis. It is observed in Amoeba.

→ Transport of Substances through Plasma Membrane: Substances can pass through plasma membrane by two processes: diffusion and osmosis.
a. Diffusion: It is the process of movement of substances from their higher concentration to their lower concentration. During respiration, CO₂ is given out as a waste product and accumulates in higher concentration inside the cell as compared to the outside medium. Due to the difference in concentration inside and outside the cell, CO₂ starts moving out of the cell.

b. Osmosis: The movement of water moleculas through a selectively permeable membrane is called osmosis. Osmosis is the movement of water from a region of higher water concentration, through a semi-permeable membrane, to a region of lower water concentration.

→ If the medium surrounding the cell has a higher water concentration than the cell, the cell will gain water by osmosis. Such a solution is known as a hypotonic solution.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 1

If the medium has exactly the same water concentration as the cell, there will be no net movement of water across the cell membrane. Such a solution is known as an isotonic solution.
If the medium has a lower water concentration than the cell, it will lose water by osmosis. Such a solution is known as hypertonic solution.

→ Cell wall: Cell wall is a non-living, thick and freely permeable covering made up of cellulose. It is available in eukaryotic plant cells and in prokaryotic cells as well. It determines the shape of the cells. It protects the plasma membrane. It prevents desiccation or dryness in cells. It helps in the transport of various substances in and out of the cell.

→ Nucleus: Nucleus is covered by a double¬layered membrane. The fluid inside the nucleus is called nucleoplasm. Nucleus consists of chromosomes which are important for the functioning of a cell. Chromosomes consist of genes which are the carriers of genetic information. Nucleus controls all the metabolic activities of the cell. It is the storehouse of genes. Without nucleus, cell can neither survive nor show specialised activities.

→ Type of cells: The cells can be categorised in two types:

Prokaryotic cell: In some organisms, DNA and RNA (genetic substances) are bound by a membrane. This membrane bound nucleus is termed as true nucleus. Prokaryotic cells are the cells in which true nucleus and membrane bound organelles are absent. They are primitive and incomplete cells. Prokaryotes are always unicellular organisms. Bacteria and blue-green algae are examples of prokaryotes.
Eukaryotic cell: Eukaryotic cells are the cells in which true nucleus and membrane bound organelles are present. They are advanced and complete cells. Eukaryotes include all living organisms (both unicellular and multicellular) except bacteria and blue green algae.

JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 2

→ Protoplasm: It is a jelly-like, viscous, colourless semi-fluid substance present in various cell organelles in colloidal form. Protoplasm consists of two parts:

Cytoplasm: It is that part of protoplasm which surrounds the nucleus. It contains the various cell organelles.
Nucleoplasm: It is that part of protoplasm which is located inside the nucleus.

Protoplasm stores vital chemicals like amino acids, proteins, sugar, etc. It is the site of some metabolic reactions.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 3

→ Cell organelles: These are small membrane bound structures suspended in the cytoplasm. They perform lots of chemical activities to support the structure and functioning of a cell. Some cell organelles are described below:
1. Endoplasmic Reticulum: Endoplasmic reticulum is a mesh-like structure which is composed of numerous tubes. It extends from the plasma membrane to the nuclear membrane. There are two types of endoplasmic reticulum, viz, smooth ER (synthesises lipids, detoxify drugs) and rough ER (synthesises proteins). Rough ER has ribosomes on its surface which give it the characteristic rough appearance.
It serves as the transport channel in the cell. Substances are transported from cell membrane to cytoplasm and to nucleus and vice-versa. ER also serves the role of packing many substances in the cell. It helps in the formation of plasma membrane and Golgi-bodies. Smooth ER helps in synthesis and transport of lipids.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 4
2. Golgi body: The Golgi apparatus, first described by Camillo Golgi, consists of a system of membrane-bound vesicles arranged approximately parallel to each other in stacks called cistemae. The materials synthesised near the ER are packaged and dispatched to various targets inside and outside the cell through the Golgi apparatus. The Golgi bodies store, modify, pack and dispatch the substances. They help in the formation of lysosomes.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 5
3. Lysosomes: Lysosomes are small sac-like structures. They are derived from Golgi complex. Lysosomes contain digestive enzymes. They are found in eukaryotic cells, mostly in animals. Lysosomes help in digestion of foreign substances and wom-out cell organelles. They provide protection against bacteria and vims. They help to keep the cell clean. During the distribution in cellular metabolism, e.g., when they get damaged, lysosomes may burst and the enzymes digest their own cell. Therefore, lysosomes are also known as suicidal bags of a cell.

4. Ribosomes: These are extremely small, dense and round bodies interspersed in the cytoplasm. Ribosomes are made up of ribonucleic acid (RNA) and proteins. In prokaryotic cell, ribosomes are of 70 S type. In eukaryotic cells, ribosomes are of 80 S type. Ribosome is responsible for protein synthesis. They are not membrane bound.

5. Mitochondria: Mitochondria are small sausage-shaped organelles. It is a double-membrane structure. Outer membrane is smooth whereas inner membrane is projected into numerous finger-like structures called cristae. Mitochondria contain their own DNA and ribosomes. They provide energy for the vital activities of living cells. They produce energy due to chemical reactions, in the form of ATPs (Adenosine Triphosphate – energy currency of the cell). Therefore, it is called ‘powerhouse of the cell’.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 6

6. Centrosome and centrioles: Centrosome is found only in eukaryotic animal cells. It is not bounded by any membrane but consists of centrioles. Centrioles are hollow cylindrical structures arranged at right angle to each other and are made up of microtubules. Centrioles help in cell division and also help in the formation of cilia and flagella.

7. Plastids: Plastids are present in most of the plant cells and absent in animal cells. They are usually spherical or discoidal in shape. These are double membrane bound organelles. Plastids also have their own DNA and ribosomes. Plastids are of three types:

Chloroplast: They are green coloured plastids containing chlorophyll. Chloroplasts manufacture food by the process of photosynthesis.
Chromoplast: They are colourful plastids. They provide colour to flowers and fruits.
Leucoplast: They are colourless plastids. They help in the storage of various substances like starch, proteins and fats.

8. Vacuoles: Vacuoles are fluid filled chambers and are often seen in many cells. Vacuoles are very large in plant cells. A plant cell usually has a single but large central vacuole. Such a vacuole fills almost the entire space inside the cell. Vacuoles are much smaller and few in number in animal cells.
Cell division: A cell divides by one of the following two processes:
i. Mitosis: Each cell divides into two daughter cells and each new cell has same number of chromosomes as the mother cell.
JAC Class 9 Science Notes Chapter 5 The Fundamental Unit of Life 7
ii. Meiosis: Each cell divides into four daughter cells, each having half the number of chromosomes as the mother cell.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 4 Structure of the Atom

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 4 Notes Structure of the Atom

→ Atoms are made up of three fundamental particles or sub-atomic particles called electrons, protons and neutrons. Protons and neutrons of an atom are almost of same mass. The mass of proton is approximately 2000 times as that of an electron.

→ Electron (e): These negatively charged particles were discovered by J.J.Thomson in 1897. In the experiment, a gas at low pressure was taken in a discharge tube made up of glass.
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 1

→ At the ends of the discharge tube, two electrodes were placed, connected to a battery for high voltage supply. The electrode connected to the negative end was known as cathode and that to the positive end as anode.

→ A stream of negatively charged particles was observed coming out of the cathode towards the anode. These particles were called electrons. The collection of negatively charged particles emitted from the cathode in the discharge tube are called cathode rays.

→ Proton (p⁺): In 1886, Goldstein observed in the same experiment, with different situation that, anode emitted positive particles which were called protons.

→ Canal rays: The positively charged radiations produced in the discharge tube from anode are called canal rays.

→ Difference between electron and proton:

Electron	Proton
Its mass is negligible.	Its mass is 1 unit.
Charge is negative.	Charge is positive.
J.J Thomson discovered it.	E. Goldstein discovered it.

→ Neutron (n): These neutrally charged particles were discovered by James Chadwick in 1932. Neutrons are present in atoms of all elements except hydrogen.

→ The structure of an atom:
1. Thomson’s Model of an atom: An atom is a positively charged sphere and the electrons are embedded in it. The magnitude of positive and negative charge is same inside an atom, so the atom is electrically neutral.
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 2
2. Rutherford’s α-particle scattering experiment’: α-particles are doubly charged helium ions. Since they have a mass of 4 u, the fast moving α-particles have a considerable amount of energy. A thin gold foil with thickness of about 1000 atoms was taken. A lot of fast moving α-particles were bombarded on this thin gold foil. After passing through the foil, α-particles hit the screen.
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 3

Following are the observations and inferences made:

Observation	Inference
a. Most of the α-particles pass through the foil without getting deflected.	a. Most of the space inside the atom is empty.
b. Some particles were deflected by small angles.	b. Positive charge of the atom occupies very little space.
c. One out of 12,000 particles rebound back.	c. All the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.

Rutherford, on the basis of this experiment, suggested ‘the nuclear model of an atom’. According to the nuclear model of an atom:
a. Most of the space inside the atom is empty.
b. At the centre of an atom, a small, heavy, positively charged nucleus is present.
c. Electrons revolve around the nucleus.
d. Total positive charge in nucleus is the same as total negative charge on all electrons of the atom as atom has net zero charge.

→ Drawback of Rutherford’s model of an atom: If any charged particle undergoes accelerated motion, it must radiate energy. Therefore, if a charged body (e;) rotates around another charged body (nucleus), it will radiate energy. Due to energy loss through the radiation, speed of electrons will decrease and eventually jt will fall into the nucleus. But such collapse does not occur and atoms are found to be quite stable.

3. Bohr’s Model of Atom: In 1913, Neils Bohr overcame the limitations of Rutherford’s model and proposed a model of atomic structure.
Following are the postulates:
a. Electrons revolve around a centrally located heavy, small and positively charged nucleus in certain discrete orbits.
b. While revolving in discrete orbits, electrons do not radiate energy.
c. These discrete orbits or shells are called energy levels. These orbits or shells are represented by the letters K, L, M, N …
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 4

→ Distribution of Electrons in Different Orbits: Distribution of electrons in different orbits (shells) is given by Bohr and Bury:
a. Maximum number of electrons present in a shell is given by 2n² (n = shell number).
For example,
n = 1 (K shell). 2n² = 2 (1)² = 2 electrons
b. The maximum number of electrons that can be accommodated in the outermost orbit is 8.
c. Electrons are not accommodated in a given shell, unless the inner shells are completely filled.

→ Atomic Number: The number of protons present in the nucleus of an atom is called its atomic number. It is denoted by Z.

→ Mass Number: Mass number is equal to the number of nucleons present inside the nucleus of an atom. It means, it is the sum of the total number of protons and neutrons of an atom. It is denoted by the letter A.
‘Mass number of element = Number of protons + Number of neutrons’
JAC Class 9 Science Notes Chapter 4 Structure of the Atom 6

→ Isotopes: Isotopes are atoms of same element having same number of protons but different number of neutrons. Isotopes have similar chemical properties but different physical properties.
For example: ¹²₆C, ¹⁴₆C

→ Uses of Isotopes:
a. An isotope of uranium (²³⁵₉₂C) is used in nuclear power plants to generate electricity.
b. An isotope of cobalt is used in treatment of cancer.
c. An isotope of iodine is used in treatment of goitre.
Isobars: Atoms of different elements having same mass number but different atomic numbers are called isobars.
For example: ⁴⁰₂₀Ca, ⁴⁰₁₈Ar

→ Valency: The electrons in the last shell of the atom are called valence electrons. These govern the chemical properties of elements. The number of valence electrons that take part in a chemical reaction is called valency of the atoms.
For example, hydrogen has only one electron in its outermost orbit, thus it requires one more electron to fill its outermost orbit (K shell). For this, hydrogen atom shares one electron with another hydrogen atom and forms Hr

→ When an electron from a higher energy level falls in an orbit of lower energy level, the difference in energy is radiated in the form of electromagnetic radiation or light. This explains why different atoms on heating or under other conditions emit light of different colours.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 3 Atoms and Molecules

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 3 Notes Atoms and Molecules

→ In 430 B.C., Democritus postulated that matter is made up of very small particles calLed “Atomos’ which means ‘indivisible’. Later, Antoine Lavoisier, from his experimental observations, established the laws of chemical combinations.

→ The Law of Conservation of Mass: This law of conservation of mass states that, the total mass of reactants is equal to the total mass of products.
For example:
A + B → C + D
(Reactants) → (Products)
Total mass of reactants = Total mass of products

→ Law of Definite Proportions: According to the law of definite proportions, in a chemical substance, the elements are always present in definite proportion by mass. For example. in water, the ratio of the mass of hydrogen to the mass of oxygen is always 1: 8.

→ After a series of experiments, Dalton concluded that all matter must be composed of tiny particles, which cannot be further divided. He called them atoms.

→ “The smallest particle of an element is called an atom.”
Atomic radius is measured in nanometer (nm).
1nm = 1 × 10⁹m
1 m = 10⁹nm
Atomic radii of hydrogen atom 1 × 10^-10 m

→ Dalton’s Postulates:

Matter is made up of atoms.
Atoms are indivisible and indestructible.
Atoms of a given element are identical in mass and in properties.
Compounds are formed by a combination of two or more same or different kinds of atoms and a chemical reaction is a rearrangement of atoms.
Atoms of different elements have different masses and chemical properties.
Atoms combine in the ratio of small whole numbers to form compounds.
The relative number and kind of atoms are constant in a given compound.

→ Elements and symbols: Dalton proposed a scheme of notation to represent elements.
JAC Class 9 Science Notes Chapter 3 Atoms and Molecules 1

→ Symbols for some elements as proposed by Dalton Symbols of some common elements

Name of the element	Latin name	Symbol
Hydrogen	–	H
Helium	–	He
Carbon	–	C
Copper	Cuprum	Cu
Cobalt	–	Co
Chloride	–	Cl
Cadmium	–	Cd
Boron	–	B
Barium	–	Ba
Bromine	–	Br
Bismuth	–	Bi
Sodium	Natrium	‘ Na
Potassium	Kalium	K
Iron	Ferrum	Fe
Gold	Aurum	Au
Silver	Argentum	Ag
Mercury	Hydrargyrum	Hg

→ Molecule: A molecule is a group of two or more atoms that are chemically bonded together and form the smallest part of an element or a compound. This can exist independently and shows all the properties of that substance.

→ Atomicity: The number of atoms constituting a molecule is referred to as its atomicity. Molecules of an element constitute same type of atoms. They may be monoatomic, diatomic or polyatomic.

Name of the element	Atomicity	Molecular formula
Helium	Monoatomic	He
Neon	Monoatomic	Ne
Argon	Monoatomic	Ar
Krypton	Monoatomic	Kr
Xenon	Monoatomic	Xe
Radon	Monoatomic	Rn
Hydrogen	Diatomic	H₂
Chlorine	Diatomic	Cl₂
Nitrogen	Diatomic	N₂
Phosphorus	Polyatomic (Tetra)	P₄
Sulphur	Polyatomic (Octa)	S₈

→ Ion: Ion is a charged particle and can be positively or negatively charged. A positively charged particle in a molecule is called cation, for example, Na⁺, Ca²⁺. An anion is a negatively charged particle in a molecule, for example, F^–, Cl^–.

→ Valency: The combining capacity of an element is known as valency. The combining capacity of the atoms to form molecules either with same or different elements is defined as valency. Valency is used to find out the number of atoms of an element that will combine with the atom of another element to form a chemical compound.

Every atom wants to become stable. To do so, it may lose, gain or share electrons.
a. If an atom consists of 1,2 or 3 electrons in its valance shell, then its valency is 1, 2 or 3 respectively, and it will lose 1, 2 or 3 electrons respectively.
b. If an atom consists of 5, 6 or 7 electrons in the outermost shell, then it will gain 3, 2 or 1 electron respectively, and its valency will be 3, 2 or 1 respectively.
c. If an atom has 4 electrons in the outermost shell, then it will share these electrons and hence its valency will be 4.
d. If an atom has 8 electrons in the outermost shell, then its valency is 0.
JAC Class 9 Science Notes Chapter 3 Atoms and Molecules 2

→ Variable valency: Some elements show more than one valency, hence, termed as variable valency elements.
For example:
Iron shows
valency II – Fe²⁺ (Ferrous ion)
valency III – Fe³⁺ (Ferric ion)

Copper shows
valency I – Cu⁺ (Cuprous ion)
valency II – Cu²⁺ (Cupric ion)

→ Chemical Formulae: The chemical formula of a compound is a symbolic representation of its composition.
Rule 1: Cross multiply the valency of elements to form a compound.
JAC Class 9 Science Notes Chapter 3 Atoms and Molecules 3

Rule 2: If compound consists of both metal and non-metal, then metal is written first. For example: In calcium chloride (CaCl₂) and zinc sulphide (ZnS), Calcium and Zinc are metals, so they are written first, whereas chloride and sulphide are non-metals.

Rule 3: If a compound is formed with polyatomic ions, then polyatomic ions are written in brackets.
For example: In aluminium sulphate [Al₂(SO₄)₃], the polyatomic sulphate ion, SO₄^2- is enclosed in a bracket before writing the subscript 3.
Here, the bracket with a subscript 3 indicates that three sulphate groups (SO₄^2-) are joined to two aluminium atoms.

Note: Compounds made up of a metal and a non-metal are called salts or ionic compounds. All the above examples are of salts.

→ Mole Concept: The quantity of a substance is expressed in terms of mole. 1 mole is also defined as the amount of substance which contains 6.022 × 10²³ units (Avogadro’s number denoted by NA).
For example 1 mole of oxygen atoms represents 6.022 × 10²³ atoms of oxygen and 5 moles of oxygen atoms contain 5 × 6.022 × 10²³ atoms of oxygen.

→ Molar Mass: The mass of 1 mole of a substance is called molar mass. Atomic mass or molecular mass in gram is equal to molar mass.
For example: Atomic mass of Fe is 56 u. Molar mass of Fe is 56 g.
Atomic mass of H₂O is 18 u. Molar mass of H₂O is 18 g.
Number of moles = \(\frac{\text { Given mass }}{\text { Molar mass }}\)

For example, number of moles in 122 g of iron will be
\(\frac{\text { Given mass }}{\text { Molar mass }}=\frac{112}{56}\) = 2 × 6.022 × 10²³ atoms.

JAC Class 9 Science Notes

JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure

September 10, 2024September 9, 2024 by Bhagya

JAC Board Class 9th Science Chapter 2 Notes Is Matter Around Us Pure

→ A pure substance consists of a single type of particles.

→ A mixture has more than one substance (element / compound) mixed in any proportion.

→ Mixtures can be separated into pure substances by appropriate separation techniques.

→ A solution is a homogeneous mixture of two or more substances. The major component of a solution is known as the solvent and the minor one is the solute. For example, sugar dissolved in water or alloy of copper and zinc or ethyl alcohol in water.

Mass percentage of a solution
= \(\frac{\text { Mass of solute }}{\text { Mass of solution }}\) × 100
Volume percentage of a solution
= \(\frac{\text { Mass of solute }}{\text { Mass of solution }}\) × 100

→ Materials which are insoluble in a solvent and have particles which are visible to naked eyes form a suspension. A suspension is a heterogeneous mixture.

→ When solids are dispersed in liquids to form a heterogeneous mixture or an opaque medium, it is called suspension.

→ Colloidal solutions are heterogeneous mixtures where particles of 1 × 10⁹ to 1 × 10^-6 m diameter, called dispersed phase, are distributed uniformly in a solvent, called dispersing medium.

→ Difference between true solutions, suspension and colloidal solutions.

True Solution	ColloidalSolution	Suspension
It is a homogeneous mixture of solute and solvent.	It appears to be homogeneous but actually it is a heterogeneous mixture of dispersed phase and dispersing medium.	It is a heterogeneous mixture.
The solute particles are very small, i.e., less than 10⁹ m in diameter.	The solute particles are between 10⁹and 10⁶ m in diameter.	The solute particles are quite large, i.e., larger than 10⁶m in diameter.
Particles of true solution are not visible to naked eye.	Particles are not visible to naked eye but can be seen with ultramicroscope.	Particles are big enough to be seen by naked eye.
The entire solution passes through filter paper.	The particles can pass through ordinary filter paper.	The particles cannot pass through filter paper.
The solute particles do not show Tyndall effect.	The particles show Tyndall effect.	The particles may or may not show Tyndall effect.
The particles do not settle down.	The particles do not settle down.	The particles may settle due to gravity.

→ Different Types of Colloids
JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure 1

→ Separation of a mixture can be done by hand-picking, sieving, winnowing, sedimentation, decantation, filtration, evaporation, distillation, fractional distillation, centrifugation, crystallisation and chromatography.

→ A physical change brings about a change in the state of matter without change in the composition or chemical nature of the substance.

→ A chemical change brings about a change in chemical properties of matter because one or more substances are transformed into a new substance.

→ Pure substances can be elements or compounds.

→ An element is a form of matter which cannot be broken down by chemical reactions into simpler substances.

→ A compound is a substance composed of two or more different types of elements, chemically combined in a fixed proportion.

→ Properties of a compound are different from its constituent elements whereas a mixture shows the properties of its constituting elements or compounds.
JAC Class 9 Science Notes Chapter 2 Is Matter Around Us Pure 2

JAC Class 9 Science Notes

JAC Class 7 Social Science Solutions History Chapter 10 Eighteenth Century Political Formations

September 10, 2024September 9, 2024 by Prasanna

JAC Board Class 7th Social Science Solutions History Chapter 10 Eighteenth Century Political Formations

JAC Class 7th History Eighteenth Century Political Formations InText Questions and Answers

Page 139

Question 1.
See Chapter 4, Table 1. Which group of people challenged Mughal authority for the longest time in Aurangzeb’s reign?
Answer:
The Marathas under the leadership of Shivaji challenged Mughal authority for the longest time in Aurangzeb’s reign.

Page 144

Question 2.
In trying to consolidate their rule, why did Mughal subadars also want to control the office of diwan?
Answer:
In trying to consolidate their rule, Mughal subadars also want to control the office of diwan because they were very ambitious, aspiring and power hungry and diwan office was the main point.

Page 148

Question 3.
What is the Khalsa? Do you recall reading about it in Chapter 8?
Answer:
Guru Gobind Singh in the seventeenth century, organised group of warriors known as Khalsa and requested the presence of the institution of Sikhs. Five persons were chosen called as Panj Pyare who took the water of immorality. There are five features which distinguish Sikhs from others.,which are known as 5Ks. These are Kesh (hair), Kara (iron bracelet), Kangha (comb), Kripan (dagger) and Kacchera (underwear).

Page 152

Question 4.
Imagine, you are a ruler of an eighteenth century kingdom. Tell us about the steps you would take to make your position strong in your province, and what opposition or problems you might face while doing so.
Answer:
In order to make my position strong, I would reform military and financial systems of my province. I would end corruption in the administration. The most expected problem would be the attack of some other kingdom. I would be ready to face any such attack.

JAC Class 7th History Eighteenth Century Political Formations Textbook Questions and Answers

Question 1.
Match the following:

subadar	a revenue farmer
faujdar	a high noble
ijaradar	provincial governor
misl	Maratha peasant warriors
chauth	a Mughal military commander
kunbis	a band of Sikh warriors
umara	tax levied by the Marathas

Answer:

subadar	provincial governor
faujdar	a Mughal military commander
ijaradar	a revenue farmer
misl	a band of Sikh warriors
chauth	tax levied by the Marathas
kunbis	Maratha peasant warriors
umara	a high noble

Fill in the blanks:

Question 2.
(a) Aurangzeb fought a protracted war in the ………..
(b) Umara and jagirdars constituted powerful sections of the Mughal ………..
(c) Asaf Jah Founded the Hyderabad state in ………..
(d) The founder of the Awadh state was …………
Answer:
(a) Aurangzeb fought a protracted war in the Deccan
(b) Umara and jagirdars constituted powerful sections of the Mughal administration
(c) Asaf Jah Founded the Hyderabad state in 1724
(d) The founder of the Awadh state was Burhan-ul-Mulk Sa’adat Khan

Question 3.
State ’T’ for true and ’F’ for false.
(a) Nadir Shah invaded Bengal.
(b) Sawai Raja Jai Singh was the ruler of Indore.
(c) Guru Gobind Singh was the tenth Guru of the Sikhs.
(d) Poona became the capital of the Marathas in the eighteenth century.
Answer:
(a) False
(b) False
(c) True
(d) True

Question 4.
What were the offices held by Saadat Khan?
Answer:
Sa’adat Khan held the integrated offices of subadari, diwani and faujdari. Actually, he was responsible for managing the political, financial and military affairs of the province of Awadh.

(Let’s Discuss)

Question 5.
Why did the Nawabs of Awadh and Bengal try to do away with the jagirdari system?
Answer:
The Nawabs of Awadh and Bengal tried to do away with the jagirdari system to decrease Mughal influence in the regions by reducing the number of officeholders (jagirdars) appointed by the Mughals. They also reduced the size of jagirs, and appointed his own loyal servants to vacant positions. The accounts of jagirdars were checked to prevent cheating and the revenues of all districts were reassessed by officials appointed by the Naw’ab’s court. In an effort to reduce the Mughal influence in Bengal, Murshid Question uli Khan transferred all Mughal jagirdars to Orissa and ordered a major reassessment of the revenues of Bengal. Revenue was collected in cash with great strictness from all zamindars. As a result, many zamindars had to borrow money from bankers and moneylenders.

Question 6.
How were the Sikhs organised in the eighteenth century?
Answer:
The Sikhs were organised in the eighteenth century in the following way:

They organised themselves into a number of bands known as jathas and later on mis Is.
They had a combined forces which was known as dal Khalsa or grand army.
In Amritsar during Baisakhi and Diwali, the whole body of people used to meet to take collective decisions called as the ‘resolutions of the Guru (gurmatas).’
Guru Gobind Singh organised
the army with the influence and inspiration that their destiny was to rule.
The well knit Sikh organisation, put a strong resistance on Mughal governors first, then to Ahmad Shah Abdali who had captured the strong province of Punjab and siezed Sarkar of Sirhind from the Mughals.
The Sikh territories in the late eighteenth century extended from the Indus to the Jamuna, but they were divided under different rulers.
One of them, Maharaja Ranjit Singh, reunited these groups and established his capital at Lahore in 1799.

Question 7.
Why did the Marathas want to expand beyond the Deccan?
Answer:
The Marathas wanted to expand beyond the Deccan to challenge and decrease the Mughal influence. By the 1720s, they seized Malwa and Gujarat from the Mughals and by 1730s, they were recognised as the overlord of the entire Deccan.

Question 8.
What were the policies adopted by Asaf Jah to strengthen his position?
Answer:
The policies adopted by Asaf Jah to strengthen his position were:

He brought trained and skilled soldiers and administrators from northern India who wanted to explore the new opportunities in the south.
He recruited mansabdars and granted jagirs to them.
Without Mughal interference, he ruled independently. The Mughals rarely confirm the decisions that were taken by Asaf Jah.

Question 9.
Do you think merchants and bankers today have the kind of influence they had in the eighteenth century?
Answer:
Merchants were more influential and powerful than the bankers in the eighteenth century than today. Banks were not so organised and merchants used to provide more loan opportunities at higher rates of interests. Nowadays, banks are more influential. They provide financial assistance and loans at lower rates and act as a shield of protection of public money. They also provide subsidy on lower rates. This happened due to the spread of education.

Question 10.
Did any of the kingdoms mentioned in this chapter develop in your state? If so, in what ways do you think life in the state would have been different in the eighteenth century from what it is in the twenty first century?
Answer:
Students need to do by their own as if they stay in any of the region where any kingdom developed.
Hint: If we take up Punjab as the region then there developed many states in the eighteenth century, the East India Company started capturing the regions and other rulers were present. But, in twenty first century, we are a democratic country.

(Let’s Do)

Question 11.
Find out more about the architecture and culture associated with the new courts of any of the following Awadh, Bengal or Hyderabad.
Answer:
The architecture and culture associated with the new courts of any one of the following:

The rulers of Awadh does not discriminate between the Muslims and Hindus. They had a very secular political policies.
Temples and mosques were constructed.
Lucknow became the cultural city due to the economic prosperity and peace in the state. Lucknow was an important city of Awadh. It also developed as an important centre of art and craft.
Students can also mention about Hyderabad and Bengal with the help of parents and teachers.

Question 12.
Collect popular tales about rulers from any one of the following groups of people: the Rajputs, Jats, Sikhs or Marathas.
Answer:
Students need to do it at their own.
(Hint : Can take inputs from various sources such as internet, books, journals and teachers.)

JAC Class 7th History Eighteenth Century Political Formations Important Questions and Answers

Multiple Choice Questions

Question 1.
Ahmad Shah Abdali invaded north India.
(a) 4 times
(b) 2 times
(c) 5 times
(d) 3 times
Answer:
(c) 5 times

Question 2.
The governors of big and large provinces were called
(a) Governor General
(b) Jagirdar
(c) Subedars
(d) Misl
Answer:
(c) Subedars

Question 3.
Shivaji was the
(a) founder of Maratha Kingdom
(b) founder of Sikh community
(c) founder of Mughal Kingdom
(d) None of these
Answer:
(a) founder of Maratha Kingdom

Question 4.
The founder of Hyderabad state was
(a) Alamgir II
(b) Sa’adat Khan
(c) Nadir Shah
(d) Nizam-ul-Mulk, Asaf Jah
Answer:
(d) Nizam-ul-Mulk, Asaf Jah

Question 5.
Bengal and Awadh were founded by
(a) Asaf Jah and Farrukh Khan
(b) Murshid Quli Khan and Sa’adat Khan
(c) Murshid Quli Khan and Asaf Jah
(d) Sa’adat Khan and Asaf Jah
Answer:
(b) Murshid Quli Khan and Sa’adat Khan

Question 6.
……… is held responsible for the decline of Mughal empire.
(a) Bahadur Shah Zafar
(b) Shahjahan
(c) Jahangir
(d) Aurangzeb
Answer:
(d) Aurangzeb

Question 7.
Raja Ajit Singh of Jodhpur held the governorship of
(a) Amber
(b) Gujarat
(c) Malwa
(d) Jaipur
Answer:
(b) Gujarat

Question 8.
Burhan-ul-Mulk Sa’adat Khan was appointed subadar of Awadh in
(a) 1722
(b) 1728
(c) 1732
(d) 1742
Answer:
(a) 1722

Question 9.
Skilled soldiers and administrators were brought by Asaf Jah from
(a) eastern India
(b) central India
(c) western India
(d) northern India
Answer:
(d) northern India

Question 10.
Before and after the establishment of the Khalsa in 1699, many battles were fought against the Rajput and Mughal rulers by
(a) Guru Gobind Singh
(b) Guru Nanak
(c) Banda Bahadur
(d) Guru Arjan Dev
Answer:
(a) Guru Gobind Singh

Very Short Answer Type Questions

Question 1.
Name three states that were sculpted out in the eighteenth century from the old Mughal provinces.
Answer:
The three states that were sculpted out in the eighteenth century from the old Mughal provinces are Awadh, Hyderabad and Bengal.

Question 2.
The Jats became powerful under whose leadership?
Answer:
The Jats becaine powerful under the leadership of Churaman.

Question 3.
Who became the leader of the Sikhs after the death of Guru Gobind Singh?
Answer:
Banda Bahadur became the leader of the Sikhs after the death of Guru Gobind Singh.

Question 4.
When and where did Nadir Shah, the ruler of Iran invaded?
Answer:
In 1739, Delhi was invaded by Nadir Shah, the ruler of Iran.

Question 5.
Which place was established as the capital during Maharaja Ranjit Singh’s reign?
Answer:
Lahore was established as the capital during Maharaja Ranjit Singh’s reign.

Question 6.
Who was Jawahir Shah and how many troops he had on his own?
Answer:
Jawahir Shah was the son of Nadir Shah and he had 30,000 troops on his own.

Question 7.
Who was the tenth Sikh guru?
Answer:
Guru Gobind Singh was the tenth Sikh guru.

Question 8.
Which two important trading centres were governed and ruled by the Jats?
Answer:
The two important trading centres governed and ruled by the Jats were Panipat and Ballabhgarh.

Question 9.
What do you understand by the term ‘chauth’?
Answer:
Zamindars claimed 25 per cent of the land revenue which was known as chauth. This was collected by the Marathas in the Deccan.

Question 10.
Which ruler raided the rich province of the Punjab and the Sarkar of Sirhind from the Mughals in mid 17th century?
Answer:
Ahmad Shah Abdali had raided the rich province of the Punjab and the Sarkar of Sirhind from the Mughals.

Short Answer Type Questions

Question 1.
When did the Khalsa declare its sovereign rule and mint its own coin? Who issued these coins and what was inscripted in the coins?
Answer:
The Khalsa declared its sovereign rule and minted its own coin in 1765. Banda Bahadur issued these coins and ‘Deg O Tegh O Fateh’ was inscripted on these coins.

Question 2.
What is the difference between Faujdari and Ijaradari.
Answer:
Military administration is related to Faujdari whereas ijaradari means the practice in which the revenue farmers collected taxes from other farmers and paid to the state.

Question 3.
Give a brief on administration of Marathas.
Answer:
The Marathas developed a powerful and effective administrative system. They established and initiated revenue demands which gradually took local conditions into account. Agriculture was encouraged and trade was revived. This allowed Maratha chiefs who were known as sardars to raise powerful armies.

Question 4.
With which states was the state of Hyderabad was in war?
Answer:
The state of Hyderabad was continuously in war against the Marathas in the west and with independent Telegu warrior chief called as Nayakas in the Deccan plateau.

Question 5.
In what manner Burhan-ul-Mulk Sa’adat Khan minimized the Mughal influence in the Awadh region?
Answer:
Burhan-ul-Mulk Sa’adat Khan tried to minimize the Mughal influence in the Awadh region in the following way:

First, he decreased the number of jagirdars, i.e., office holders appointed by the Mughals.
He also decreased the size of the jagirs and appointed their own loyal and faithful servants to unoccupied positions.
Jagirdars accounts were checked to prevent cheating and revenues of all regions were re-assessed by officials who were appointed by Burhan-ul- Mulk.

Question 6.
What do you mean by sardeshmukhid Who possessed the right to levy it?
Answer:
Sardeshmukhi means that in the Deccan 9-10 per cent of the land revenue paid to the head revenue collector. Maratha king possessed the right to levy it in the entire Deccan region.

Question 7.
Which foreign invader came in the middle of the economic and political crisis in 1739? What was the effect of it?
Answer:
Nadir Shah, the-.ruler of Iran came in – the middle of the economic and political crisis in 1739. He seized and raided the city of Delhi in 1739 and took away huge amounts of wealth. This invasion was followed by the Afghan ruler Ahmad Shah Abdali who had a series of devastating raids in north India for five times between 1748 and 1761.

Question 8.
What steps were taken by Murshid Quli Khan to reduce the effect and influence of the Mughals in Bengal ?
Answer:
Murshid Quli Khan transferred all the Mughal jagirdars to Orissa and ordered a major re-assessment of the revenues of Bengal to reduce the Mughal influence. Cash was collected as revenues with strictness from all zamindars. Hence, all the zamindars had to borrow money from moneylenders and those who were unable to pay, they were forced to sell their lands and assets to big and rich zamindars.

Question 9.
In which way moneylenders and bankers achieve influential position in the state of Awadh?
Answer:
The state of Awadh depended on local bankers and mahajans for loans and sold the right to collect tax to the highest bidders. These ‘revenue farmers’ were known as ijaradars who agreed to pay the state a fixed sum of money. The revenue – farmers were given eminent freedom in the assessment and collection of taxes. All these developments enabled new social groups such as moneylenders and bankers to influence the management of the state’s revenue system something which had not occurred in the past.

Question 10.
During the late seventeenth and eighteenth centuries, how did the Jats integrated and merged their power?
Answer:
During the late seventeenth and eighteenth centuries the Jats were flourishing and successful agriculturists. They had integrated their power under Churaman, their chief. They captured territories situated to the west of the city of Delhi and by the 1680s they had begun to rule the region between the two imperial cities of Delhi and Agra. Panipat and Ballabhgarh became important trading centres in the areas ruled by them. The kingdom of Bharatpur emerged as a strong state under Suraj Mai.

Long Answer Type Questions

Question 1.
Explain the reasons of decline of Mughal empire.
Answer:
Decline of Mughal empire in the seventeenth century happened due to following reasons:

Emperor Aurangzeb exhausted and spent his military and financial resources of empire by fighting a long battle in the Deccan.
Ii became very tough and difficult for later Mughal Emperors to regulate the powerful mansabdars.
The governors and mansabdars established independent kingdoms in different areas.
Peasants and zamindars became rebellions due to increasing taxes.
Nadir Shah seized and raided the city of Delhi in 1739 and took away huge amounts of wealth.
This invasion was followed by the Afghan ruler, Ahmad Shah Abdali, who invaded and raided north India five times between 1748 and1761
Thus the empire was further incapacitated by the competition amongst different groups of nobles.

Question 2.
Discuss briefly the states of the eighteenth century into three overlapping groups.
Answer:
The states of the eighteenth century can be separated into three overlapping groups:

States such as Awadh, Bengal and Hyderabad were old Mughal provinces. Though they were extremely powerful and quite independent, the rulers of these states did not break their formalities with the Mughal emperor.
States that had enjoyed considerable independence under the Mughals were watan jagirs. These included several Rajput principalities. Watan jagirs were the persons who collected taxes from each village and gave them to mansabdars and mansabdars gave the taxes to the state authority.
The last group included states under the control of Marathas, Sikhs and some others like the Jats. These were of different sizes and had seized their independence from the Mughals after a long-drawn armed struggle

Question 3.
Discuss briefly the states of the eighteenth century into three overlapping groups.
Answer:
The states of the eighteenth century can be separated into three overlapping groups:
1. States such as Awadh, Bengal and Hyderabad were old Mughal provinces. Though they were extremely powerful and quite independent, the rulers of these states did not break their formalities with the Mughal emperor.

2. States that had enjoyed considerable independence under the Mughals were watan jagirs. These included several Rajput principalities. Watan jagirs were the persons who collected taxes from each village and gave them to mansabdars and mansabdars gave the taxes to the state authority.

3. The last group included states under the control of Marathas, Sikhs and some others like the Jats. These were of different sizes and had seized their independence from the Mughals after a long-drawn armed struggle.

Question 4.
How did Sikhs appear as a stronger community?
Answer:
During seventeenth century, Sikhs became political community. The Khalsa was established to protect the Sikh community from the Mughals. Under Guru Gobind Singh, they fought many battles against the Mughals. After the death of Guru Gobind Singh, Banda Bahadur established the administration over the territories between Sutlej and Jamuna. In this manner Sikhs appeared as a stronger community.

JAC Class 7 Social Science Solutions

JAC Class 9 Science Notes Chapter 14 Natural Resources

September 10, 2024September 8, 2024 by Bhagya

JAC Board Class 9th Science Chapter 14 Notes Natural Resources

→ Various material resources derived from the nature for the benefit of mankind are called natural resources.

→ The life supporting zone of earth is called biosphere. It has two components:
a. Biotic components: include all the living things, e.g., forests, animals, humans, etc.
b. Abiotic components: include all the non-living things, e.g., air, water, land, etc.

→ Air: It is an inexhaustible natural resource essential for the sustenance of life. The thick blanket of air that surrounds the earth is called atmosphere. This atmosphere keeps the average temperature of the earth fairly steady.

→ Wind: Moving air is called wind. In coastal areas, the uneven heating of land and water creates winds. During day, the direction of wind is from sea to land (sea breeze) while at night, wind blows from land to sea (land breeze).

→ Rain: When water bodies are heated during the day, water vapour goes into the air. As air rises, it expands and cools forming tiny water droplets? These droplets grow bigger by condensation and fall down as rain.

→ Air pollution: Presence of undesirable and harmful substances in the air causes air pollution. Burning fossil fuels release oxide of nitrogen and sulphur in air which in turn causes acid rain. Smoke and fog in air reduce visibility and form smog.

→ Water: 97% of the water on earth is in oceans and only 3% is fresh water. Of this 3%, only 1 % is available for use and the rest is present in glaciers. Rainwater harvesting improves the availability of fresh water. It is essential for the growth and sustenance of plants and animals.

→ Water pollution: Pollution of water can occur in three ways;
a. by addition of undesirable substances,
b. by removal of desirable substances, and
c. by change in temperature.

→ Chemical fertilizers and pesticides pollute underground water. Chemicals released by industries and water released by dams also pollute water. This also destroys the life- forms in those water bodies.

→ Soil: Soil is formed by various physical, chemical and some biological processes. Sun, water and wind, all contribute to the formation of soil. Some organisms, like lichens, grow on rocks and release chemicals which cause the rock surface to powder down into soil.

→ Soil is composed of different sizes of particles which decide the soil type.

→ Soil pollution: Modem farming practices which use chemical fertilizers and pesticides are harmful for the soil. We should use the soil sustainably and plant trees to prevent soil erosion.

→ Biogeochemical cycles: The cycles in nature which keep replenishing the various natural resources in atmosphere and on the earth’s crust are called biogeochemical cycles.
a. Water-cycle: It is the constant exchange of water among the air, land and sea and between living organisms and their surroundings.
JAC Class 9 Science Notes Chapter 14 Natural Resources 1
b. Nitrogen-cycle: Nitrogen, an important nutrient for all life forms, is circulated through the living and non-living components of the biosphere through various processes like nitrogen fixation (by nitrogen fixing bacteria), ammonification, nitrification and denitrification.
JAC Class 9 Science Notes Chapter 14 Natural Resources 2
c. Carbon-cycle: Carbon is incorporated into life forms by the process of photosynthesis and returns to the atmosphere through respiration, decomposition, combustion, etc.

d. Oxygen-cycle: Green plants release oxygen by photosynthesis which is cycled during combustion and respiration.
JAC Class 9 Science Notes Chapter 14 Natural Resources 4

→ Greenhouse effect: Greenhouse gases like CO₂, CH₄, etc., trap the solar energy and keep the earth warm. This is called greenhouse effect. However, excess of such gases in atmosphere results in heating up of the earth and increase the average temperature across the globe. This is called global warming which has numerous ill-effects like melting of glaciers, floods, draughts, etc.

→ Ozone (O₃): Ozone layer is present like a blanket around the earth in the stratosphere. It absorbs the harmful UV radiations from the sun and hence protects us. However, the presence of compounds like CFCs in the atmosphere depletes the amount of ozone. An ozone hole, formed by thinning of ozone, is found over Antarctica. Hence, there is a need to take precautionary measures and lifestyle changes to conserve and procure the nature.

JAC Class 9 Science Notes

JAC Class 10 Social Science Important Questions Economics Chapter 3 Money and Credit

September 10, 2024September 6, 2024 by Prasanna

JAC Board Class 10th Social Science Important Questions Economics Chapter 3 Money and Credit

Multiple Choice Questions

Question 1.
“Money is what money does” who said?
(a) Crowther
(b) Robertson
(c) Walker
(d) Marshall
Answer:
(c) Walker

Question 2.
Direct exchange of goods against goods is called
(a) Charter
(b) Money
(c) Walker
(d) None of these
Answer:
(c) Walker

Question 3.
What possess general acceptability?
(a) Bank draft
(b) Money
(c) Bill of exchange
(d) None of these
Answer:
(b) Money

Question 4.
Which type of deposits gives highest rate of interest?
(a) Current deposit
(b) Fixed deposit
(c) Recurring deposit
(d) None of these
Answer:
(b) Fixed deposit

Question 5.
Which bank deals with short-term credit?
(a) Agricultural bank
(b) Commercial bank
(c) Industrial bank
(d) None of these
Answer:
(b) Commercial bank

Question 6.
Which of the following is not the function of the commercial bank?
(a) Issue of paper notes
(b) Acceptance of deposits
(c) Advancing loans
(d) Credit control
Answer:
(a) Issue of paper notes

Question 7.
Which of the following is not near money?
(a) Paper notes
(b) Treasury bill
(c) Bond
(d) Bill of exchange
Answer:
(a) Paper notes

Question 8.
Which bank is called lender of last resort?
(a) Commercial bank
(b) Agricultural bank
(c) Industrial bank
(d) Central bank
Answer:
(d) Central bank

Question 9.
In which year the Reserve Bank of India was established?
(a) 1945
(b) 1947
(c) 1935
(d) 1953
Answer:
(c) 1935

Question 10.
Which bank enjoys monopoly power of Note issue?
(a) NABARD
(b) Commercial Bank
(c) Central Bank
(d) Nope of these
Answer:
(c) Central Bank

Very Short Answer Type Questions

Question 1.
Why are transactions made in money?
Answer:
A person holding money can easily exchange it for any commodity or service that he or she might want.

Question 2.
Define Double Coincidence of Wants.
Answer:
In the barter system, when the demand of two persons for each other’s commodity is raised at the same time, it is called Double Coincidence of Wants.

Question 3.
Mention the modern form of money.
Answer:
Modern forms of money include currency – paper notes and coins.

Question 4.
What is the main function of the Reserve Bank of India?
Answer:
The Reserve Bank of India issues currency notes on behalf of the central government and supervises the functioning of formal sources of loans.

Question 5.
What does loan agreement specify?
Answer:
Loan agreement specifies an interest rate, mode of repayment, collateral and necessary documentation.

Question 6.
Why do farmers require credit?
Answer:
Farmers require credit to purchase seeds, fertilizers, pesticides and for irrigation purposes.

Question 7.
What is ‘credit’?
Answer:
Credit (loan) refers to an agreement in which the lender supplies the borrowers with money, goods or services in return for the promise of future payment.

Question 8.
What are informal sectors of loan?
Answer:
Informal sectors of loan include money-lenders, traders, employers, relatives and friends, etc.

Question 9.
What are the formal sectors of loan?
Answer:
Formal sectors of loan include all the banks and cooperatives.

Question 10.
Which is the newer way of providing loans to the rural poor, particularly women?
Answer:
Self Help Groups.

Short Answer Type Questions

Question 1.
Define money.
Answer:

Money refers to a medium of exchange used in economic transactions or in exchange of goods and services.
Transactions are made in money because it eliminates the inconvenience of barter system of exchange. In an economy, where money is in use, it eliminates the need for double coincidence of wants by providing the crucial intermediate step.
The use of money spans a very large part of our everyday life. There are several transactions involving money in any single day.

Question 2.
What is a demand deposit? List two advantages of demand deposits.
Answer:
A demand deposit is a deposit with the bank that people have the provision to withdraw the money as and when they require. Since the deposits in the bank accounts can be withdrawn on demand, these deposits are called demand deposits. Advantages of demand deposits:

Demand deposits earn an amount as interest.
They act as a medium of exchange like money. They constitute money in the modern economy. They are accepted widely as a means of payment by way of a cheque instead of cash.

Question 3.
What is a cheque? What is the advantage of using a cheque for payment?
Answer:
A cheque is a paper instructing the bank to pay a specific amount from the person’s account to the person in whose name the cheque has been issued. For payment through a cheque, the payer who has an account with the bank prepares a cheque for a specific amount. Advantages of using a cheque for payment:

We issue cheques against demand deposits, which make it possible to directly settle payments without the use of cash.
Since demand deposits are accepted widely as a means of payment along with currency, they constitute money in the modem economy.

Question 4.
Differentiate between the terms of credit offered in formal and informal sectors of credit.
Answer:

Formal Sector	Informal Sector
(i) RBI supervises their function of giving loans.	(i) No organization is there to supervise its lending activities.
(ii) Collateral is required to obtain credit.	(ii) This sector gives loans without collateral.
(iii) The rate of interest is comparatively low than that of the informal sector , loans.	(iii) Higher interest rates on loan are charged.

Question 5.
What are the various purposes for which the rural people require credit?
Answer:
The various purposes for which the rural people require credit are:

People in rural areas generally require credit to meet the expert civilities.
In the case of crop failure, they take fresh loans for cultivation and to repay previous debt. In this situation, the credit pushes the person into a debt trap.
Also, they require a loan to meet the daily expenses such as expenses for sudden illness or functions in the family.

Question 6.
Explain any three terms of credit.
Answer:
Three terms of credit are as follows:

Interest rate which the borrower must pay to the lender along with repayment of the principle.
Collaterals such as land titles, deposits with banks, livestock, etc., and documentation required.
Mode of repayment: This means how the borrower would repay the lender his/ her loan amount. For example, on the monthly, quarterly, half – yearly or yearly basis. They may vary depending on the nature of the lender and the borrower. The terms of credit vary substantially from one credit arrangement to another.

Question 7.
Why do poor farmers get into debt trap of informal sector?
Answer:
There are several reasons behind it. These are:

There is no organisation which supervises the credit activities of lenders in the informal sector.
They can lend at whatever interest rate they choose.
There is no one to stop them from using unfair means to get their money back.
Compared to the formal lenders, most of the informal lenders charge a much higher interest rate on loans. So, the cost to the borrowers of informal loans is much higher.
Higher cost of borrowing meanS a larger part of the earnings of the borrower is used to repay the loan.
The higher interest rate of borrowing can mean that the amount to be repaid is greater than the income of the borrower. This could lead to increasing debt and debt trap.

Question 8.
Explain with an example, how credit plays a vital and positive role for development.
Answer:
Cheap and affordable credit plays a vital and positive role for the country’s development.

Credit helps in increasing the economic activities of the borrowers.
A large number of transactions in our day- to-day activities involve credit in some form or the other.
It may be helpful in growing crops, doing business, setting up small-scale industries, trade in goods, etc.
If credit is available to the poor people on reasonable terms and conditions, they can improve their economic condition which in turn, will help them to have a better standard of living.

Question 9.
State any three advantages of an ATM.
Answer:
The three advantages of an ATM are as follows:

The full form ATM is Automated Teller Machine.
In case of an ATM, direct interaction with the bank is not required.
Money can be withdrawn from the ATM any time twenty-four hours in a day, whereas banks close their public dealings at a particular time, binding the depositor to come within that stipulated period.

Long Answer Type Questions

Question 1.
What is the role of a bank in the economic development of a country? Explain.
Answer:
Banks play a major role in the economic development of a country. These are as follows:

Banks mediate between those who have surplus money and those who need money. They take deposits from those who have surplus money and use the major portion of the deposits to extend loans.
They account for 25% of rural credit in India. In this way, they help in increasing the economic activities of the borrowers.
In India, banks give loans not just to profit-making businesses and traders but also to small cultivators, small-scale industries, small borrowers, etc.
Cheap and affordable credit is crucial for the country’s development. It helps to grow crops, to meet working capital needs of production and in setting up new industries or trade in goods.
They help poor people to increase their standard of living. If credit is available to poor people at a low rate of interest and on reasonable terms and conditions, they can improve their economic conditions.

Question 2.
What are the commercial banks? Mention any four of their functions.
Answer:
A commercial bank or a bank is a profit-making institution that accepts the deposits, pays an amount as interest on the deposits and extends loans to the needy people. The following are the functions of a commercial bank:

Commercial banks accept the deposits from those who have surplus money.
They pay an amount as interest on the deposits.
Banks in India hold about 15% of their deposits as cash as a provision to pay the depositors who might come to withdraw money from the bank on any given day and use the major portion of the deposits to extend loans.
They mediate between those who have surplus funds and those who are in need of these funds. They charge a higher interest rate on loans than what they offer on deposits.
The difference between what is charged from the borrowers and what is paid to the depositors is their main source of income.

Question 3.
What are formal sources of credit? Why do we need to expand formal sources of credit in India?
Answer:
The formal source of credit includes a loan from banks and co-operatives. We need to expand formal sources of credit in India for the following reasons:

Formal sources of credit are less risky and they charge a low rate of interest.
The Reserve Bank of India supervises the functioning of formal sources of loans. It monitors the banks in actually maintaining a cash balance.
RBI ensures that loans are given not only to the profit-making businessmen and traders but also to small cultivators, small- scale industries, small borrowers, etc.
Compared to the formal lenders, most of the informal lenders charge higher interest rates. Thus, the cost to the borrower becomes much higher that leads to less income. Also, the borrowers may become victim to debt – trap. So, formal sector loans help reduce dependence on informal sources of credit.
Due to the high interest rates of the informal source of credit, people who might wish to start an enterprise by borrowing, may not do so because of the high cost of borrowing.
Cheap and affordable credit by the formal sector is crucial for the country’s development.

Question 4.
Explain the term ‘debt – trap’. Why is it more rampant in rural areas? Give two reasons.
Answer:
When the credit pushes the borrower into a situation from which the recovery is very painful, it is called debt – trap. For example, in the case of crop failure small or marginal farmers have to sell a portion of his/her land to repay the loan. The debt – trap is rampant in rural areas because of the following reasons:

Farmers take loans for crop production, equipment, fertilizers, etc. If crop failure happens due to any reason, they become unable to pay back the loan.
There is usually an absence of any kind of support to the fanners in case of crop failure. So, they are clearly much worse off than before.

Question 5.
What are the Self – Help Groups? How do they work? Explain.
OR
“Self – Help Groups play an important role in solving the problems of rural poor.” In this context explain the social and economic values attached to it.
Answer:
1. It promotes women empowerment. SHGs are the groups created by needy persons themselves, especially women to fulfil their credit and loan needs. A typical SHG has 15 – 20 members, who meet and save regularly. So, through SHGs, women become economically independent. They are engaged in economic activities. Their voices are heard in the family and society,

2. The SHG encourages teamwork because it is an organization of about 15-20 members who meet and save at a regular interval.

3. The Self-Help Group leads to self sufficiency to its members. Members can take small loans from the group itself to meet their needs. If the group is regular in savings, it can avail loans from the bank that is meant to create self-employment opportunities for the members.

4. They are helpful in the eradication of poverty. This is because, the SHG provides cheap loans to its members to start self – employment activities such as establishing business units, shops, small trading, etc. In this way, they increase their incomes which leads to the eradication of poverty.

5. The SHG is a source of inspiration to its members. Inspiration refers to an unconscious burst of creativity in an artistic endeavour. It is a directing agent for a man to seek some purpose in life. Also, it controls the obstacles.

Activity Based Questions

Question 1.
The following table shows people in a variety of occupations in urban areas. What are the purposes for which the following people might need loans? Fill in the column.

Occupations	Reason for need of a Loan
Construction worker
Graduate student who is computer literate
A person employed in government service
Migrant labourer in Delhi
Household maid
Small trader
Autorickshaw driver
A worker whose factory has closed down

Next, classify the people into two groups based on whom you think might get a bank loan
and those who might not. What is the criterion that you have used for classification?
Answer:

Occupations	Reason for need of a Loan
Construction worker	To meet a medical emergency in the family
Graduate student who is computer literate	To pay the fees for a higher degree
A person employed in government service	To purchase a flat
Migrant labourer in Delhi	For expenses related to his daughter’s wedding
Household maid	To meet the daily expenses
Small trader	To run his business efficiently
Autorickshaw driver	To replace his old auto rickshaw with a new one
A worker whose factory has closed down	To meet his expenses till he gets employed again

Question 2.
Classification Regarding Ability to get a Loan
Answer:
The criteria I have used for this classification are:
1. Does the borrower have the potential to repay the loan or not?
People with a secure job or a running business will get a loan because they have the capability to repay the instalments. Here the government servant and small trader will be successful, whereas the migrant labourer, household maid, construction worker and worker whose factory has closed down will not be successful.

2. Whether the borrower is able to pledge collateral on which to guarantee the loan taken.
Here the auto rickshaw driver can pledge his auto rickshaw to the bank and the graduate student can pledge any capital asset owned by him. These two are the basic prerequisites for getting a loan from a bank.

Question 3.
Read the statement given below and answer the questions that follow:
(a) Which are the two major sources of credit for rural households in India?
Answer:
Moneylenders and Cooperative Societies

(b) Which one of them is the most dominant source of credit for rural households?
Answer:
Moneylenders

Moneylenders do not ask for collateral.
Complicated paper work or documentation is not involved.