EX- (P: 5-6)

A 1. D 2. E 3. C 4. B 5. A

B 1. a cell 2. organelles 3. cell membrane 4. cellulose 5. a tissue 6. red blood cells

C: Answer the Questions:

Q No. 1

Define an amoeba.


The amoeba is a unicellular organism that lives in water and wet soil.

Q No.2

Why are cells called the building blocks of life?


Cells make up living things in the same way that bricks are used to build a house.

Q No.3

Draw a Venn diagram, like the one given below, in your notebook to show how plants and animals are similar and how they are different.

(Write the names of the parts/features.)


Venn diagram

Features found in animal cells

Vacuole nucleus cytoplasm cell membrane

Common features

Vacuole nucleus cytoplasm cell membrane

Features found in plant cells

Vacuole cell membrane cell wall nucleus cytoplasm

Q No.4


CELL MEMBRANE: It allows certain materials to go in and out of the cell.

CHLOROPLAST: It absorbs the Sun’s energy and helps the plant to make its food.

VACUOLE: It stores food, water, and waste substances.

CYTOPLASM All the organelles are suspended or floating in it.

NUCLEUS: It controls all the activities of the cell.

U: 2                 THE BRAIN

EX- (P: 10-11)

A 1. C 2. D 3. A 4. B

B 1. b) reproduce 2. a) cerebrum 3. c) cerebrum 4. a) cerebrum

  1. c) medulla

D: Answer the Questions:

Q No. 1

What is a neuron and how does it function?


Neurons are the nerve cells which make up the brain. They are linked together to control all of the body’s activities.

Q No.2 What can a brain do that a computer cannot do?
Q No.3

Draw a neat end well-labelled diagram of the brain to illustrate the three parts of the brain you have read in this U.

Q No.4

Write a positive, a negative and an interesting thing which could happen if you had two brains?

Q No.5

Construct the following table in your notebook. Write five activities each of your daily routine which involves the help of the three parts of the brain.



1 reading a book           walking             breathing

2 solving a math problem   jumping             digesting

3 writing a story         taking exercise       heart beating

4 listening to music         running

5 eating my favourite dish   boxing


U: 3          THE LUNGS

EX- (P: 16-17)

A 1. True 2. True 3. False 4. False 5. True 6. True

B 1. mucus 2. diaphragm 3. trachea 4. oxygen, carbon dioxide 5. exhaled 6. alveoli or air sacs 7. ribcage


C: Answer the Questions:

Q No. 1

Explain what is meant by respiration.


Respiration is the process of obtaining oxygen from the air and its use by cells to produce energy.

Q No.2

Where inside your body are your lungs located, and what is their main function?


The lungs are located within the chest and are protected by the ribcage. The main function of the lungs is to provide the body with the oxygen it needs to produce energy from food.

Q No.3

Why do you need to breathe in oxygen?


Oxygen is needed to produce energy from food.

Q No.4

What is mucus? What is its function?


Mucus is a sticky substance produced by the nose and trachea. Its function is to trap dust particles and some bacteria before the air enters the lungs.

Q No.5

Why is there tiny hair in the trachea?

ANS: The tiny hairs in the trachea, called cilia, sweep out the dust caught in the mucus. They help to keep the lungs clean.
Q No.6

What is the diaphragm and what does it do?

ANS: The diaphragm is a sheet of muscle which separates the lungs from the abdomen. It helps the lungs to expand and contract when we breathe in and out.
Q No.7
ANS: nose trachea   bronchus lungs alveoli

U: 4          THE HUMAN HEART

EX- (P: 21-22)

A 1. E 2. A 3. D 4. B 5. C

B 1. a 2. b 3. c 4. c 5. c 6. b 7. a

D: Answer the Questions:

Q No. 1

What is the function of the heart?


The function of the heart is to pump oxygenated blood to all parts of the body.

Q No.2

Explain what is meant by:

a)       oxygenated blood

b)       deoxygenated blood


a) Oxygenated blood means blood rich in oxygen. It is also called pure blood.

b) Deoxygenated blood means blood which has more carbon dioxide and less oxygen. It is also called impure blood.

Q No.3

What is the role of the lungs in the circulation of blood in your body?


The lungs play an important role in the circulation of blood. The exchange of gases takes place in the lungs: oxygen is absorbed into the blood and carbon dioxide is released from the blood.

Q No.4

Explain the function of each of the following:

a)       Pulmonary artery

b)       Pulmonary vein

c)       Aorta

d)      Coronary artery


a) The pulmonary artery takes the deoxygenated blood from the heart to the lungs.

b) The pulmonary vein takes the oxygenated blood from the lungs to the heart.

c) The aorta is the largest artery of the body and sends blood to all parts of the body.

d) The coronary artery provides the blood to the heart.

Q No.5



   Eat a balanced and healthy diet.

2. Exercise regularly or be physically active.

3. Do not smoke.

4. Maintain a healthy weight.

5. Be screened by your doctor to determine your risk of heart disease. Know your blood pressure and cholesterol level.

  1. Reduce intake of fizzy drinks and energy drinks.















U: 5                DIGESTION

EX- (P: 25-26)

A The mouth has special glands that produce saliva which softens and moistens food. The tongue pushes the food into the throat, from where it passes into a tube, called the esophagus.

It is then pushed into the stomach which works like a mixer. The stomach releases hydrochloric acid which kills harmful bacteria.

The food now enters a long, narrow tube called the small intestine. Here, more juices are added to the food by other organs like the liver, the pancreas and the gall bladder.

Now the food gets absorbed into the blood, while the waste material is passed into the large intestine.

B 1. b) digestive system 2. c) stomach 3. a) mouth

  1. c) simply moved to the next organ 5. c) is absorbed into the blood 6. c) small intestine 7. b) large intestine

C: Answer the Questions:

Q No. 1

Why do you need to digest food?


We need to digest food because food cannot go straight to the cells. It has to be broken down into simpler substances so that it can be absorbed into the blood easily.

Q No.2

Explain what happens to the food in the:

a) oesophagus                      b) stomach                     c) small intestine


a) The muscles of the esophagus squeeze and relax to push the food into the stomach.

b) Food is stored in the stomach where it is mixed with some digestive juices and hydrochloric acid. The juices and hydrochloric acid help to soften the food. The acid kills the harmful bacteria present in the food.

c) In the small intestine, more juices that are produced by the liver, pancreas and gall bladder are added to the food. These juices make the food even softer and simpler. Then the food is absorbed into the blood through the walls of the small intestine.

Q No.3

How does saliva help in the process of digestion?


Saliva helps to moisten and soften the food and starts the digestion of starches.

Q No.4

What is the function of the kidneys?


The kidneys help to remove the waste materials and excess water from the body.

Q No.5

Where does the small intestine get digestive juices from?


The digestive juices in the small intestine come from other organs such as the liver, pancreas and gall bladder.

Q No.6

Draw a neat diagram of the digestive system and label the following part in it:

mouth, oesophagus; stomach, small intestine, large intestine




EX- (P:31-33 )

A ‘Compare the milk sold by your Iocal milk seller to packaged milk,
Think which one is healthier to drink and why. Then put a tick or a cross next to each statement below:

  1. Milk sold by the milk seller can be drunk without boiling it first.
  2. Microorganisms are able to grow in pasteurized and sterilized milk. Packaged milk is pasteurized milk. .
  3. Packaged milk is pure and lasts longer than the milk sold by the milk seller.
  4. Milk is boiled or pasteurized to kill the microorganisms growing in it.

ANSWERS: a) ✗ b) ✗ c) ✔ d) ✔ e) ✔

B 1. Some bacteria are harmful, while some are useful.

  1. Typhoid is caused by a microorganism called bacteria.
  2. The study of microorganisms is known as microbiology.
  3. Athlete’s foot is caused by fungi.
  4. A useful type of bacteria is used in making yogurt.
  5. Milk is preserved by a process called pasteurization.
  6. Protozoan is a unicellular organism, while fungus is a multi cellular organism.
  7. A mushroom is an example of edible fungi.
  8. Food can be preserved by freezing, canning through chemical preservation.
  9. Harmful microorganisms are commonly called germs.

C 1. b) microorganisms 2. a) dysentery 3. b) tooth decay 4. c) fungi 5. b) bacteria 6. a) fungi 7. c) 60 degrees Centigrade 8. b) dry and frozen 9. a) food 10. a) Microorganisms are all around us.

D: Answer the Questions:

Q No. 1

Define the following terms:

a) microorganism         . b) microscopic


a) Microorganisms are tiny living things that can only be seen through a microscope.

b) Something that is so small that it can only be seen through a microscope is called microscopic.

Q No.2

Name any three places where you can find bacteria.

Q No.3

How are fungi useful for human beings? Write two examples.

Q No.4

List six ways in which microorganisms can enter the body.

Q No.5

What happens to food that is not preserved?


If food is not preserved, it decays and becomes inedible.

Q No.6

Look at the different foods below. Which of these can be preserved by freezing, by pasteurizing and sterilizing, and by adding chemical preservatives?


milk – pasteurization

chicken – chemical preservative and freezing

fruit juice – canning and bottling

ice cream – freezing

tomato paste – canning and bottling

yogurt – pasteurization

fruit jam – chemical preservatives, canning and bottling



EX- (P: 37-38)

A 1) D sensitivity 2) C excretion 3) B nutrition 4) A reproduction

B 1. Plants can make their own food by a process called photosynthesis.

  1. All living organisms have seven characteristics that make them different from non-living things.
  2. Plants and animals take in oxygen and let out carbon dioxide. This process is called respiration.
  3. Animals can move from place to place. This movement is called locomotion.

C 1. b) sensitivity 2. b) plants make their own food 3. a) grow and change 4. b) reacting to one’s environment 5. a) for energy to grow and be active

D: Answer the Questions:

Q No. 1

What is the one most important thing that plants can do but animals cannot do?


Plants can make their own food but animals cannot do so.

Q No.2

Why do animals move from place to place?


Animals move from place to place in search of food.

Q No.3

Explain how animals movements are different than those of plants?


Animals’ movements are called locomotion.

Plants do not move from place to place in search of food as they are able to make their own food.

Q No.4

Give one example of growth in plants and animals?

Q No.5

Make a list of the seven characteristics of all living things?


  1. All living things need food.
  2. All living things respire.
  3. All living things excrete.
  4. All living things have sensitivity.
  5. All living things can move by themselves.
  6. All living things grow.
  7. All living things reproduce.


EX- (P: 43-45)

  • The process by which all living things make new organisms is known as———————
  • The physical changes that take place during the life cycle of an animal are known as the ———————————
  • The ————————metamorphosis has more than three stages in the life cycle of an organism.
  • The —————— metamorphosis has more than three stages in the life cycle of an organism.
  • Tadpoles live in water and breathe through————————————
  • When a single parent cell reproduces as a new organism, it is not an exact———————– of its parent cell.
  • The female reproductive cell is called a / an————————while the male reproductive cell is called the ——————–.

A 1. reproduction 2. metamorphosis 3. incomplete 4. complete 5. gills 6. copy 7. egg, sperm

B 1. c reproduction 2. b three 3. b gills 4. c become extinct 5. c pupa 6. b microorganism

D: Answer the Questions:

Q No. 1

Define the following terms:

a) Reproduction          b) Metamorphosis


a) Reproduction is the process by which plants and animals make copies of themselves.

b) The physical changes that happen to an organism during its life cycle are known as metamorphosis.

Q No.2

Why is animal reproduction important?


Reproduction is very important in animals because without it the animal species would die out, or become extinct.

Q No.3

Compare between the following with examples of each type.

a)        Two ways of reproduction in living things.

b)Complete and incomplete metamorphosis.

ANS: a) Two ways of reproduction in living things:
            Sexual reproduction Asexual reproduction
This needs two parent cells to reproduce a new organism. One cell, the sperm, comes from the male parent, and the other cell, the egg, comes from the female parent. The new organism has the qualities of both of the parents. This needs only one cell in order to reproduce the new organism.

The new organism is an exact copy of its parent.

b) Complete and incomplete metamorphosis:
Complete Metamorphosis Incomplete Metamorphosis
In the complete form of metamorphosis an insect passes through four separate stages of growth, as embryo or egg , larva, pupa, and adult. The life cycle of certain insects, such as crickets and grasshoppers, is characterized by the absence of a pupa stage between the immature and adult stages. Such a life cycle is known as incomplete metamorphosis.
Q No.4

Look carefully at the pictures of life cycle of two insects given on pages 42. For each insect shown, describe what happens at each stage.


Life cycle of a grasshopper

The female grasshopper lays eggs.

1. The nymph hatches from an egg.

2. As the nymph grows, it sheds its ‘skin’ or exoskeleton.

3. An adult grasshopper emerges after the nymph stage.

Life cycle of a butterfly

1. The female butterfly lays its eggs on a leaf or stem.

2. The caterpillar (or larva) is the long, worm-like stage of the butterfly or moth. It is the feeding and growth stage.

3. This caterpillar changes into a pupa.

4. A colourful adult butterfly or moth appears from the case of the pupa.

Q No.5

Rearrange the stages ·of a frog’s life cycle in the proper sequence. Write the correct sequence number in the given space.

a)      The tadpole turns into an adult frog and is capable of reproducing new frogs. Now it can live both on land and in water.—————————–

b)      Then the gills and tail disappear. The lungs grow.————————–

c)      The baby frog, called a tadpole, hatches from the egg and starts swimming in water with the help of its tail. It breathes through its gills.————————-

d)      The frog lays its eggs in water.————————————-

e)      It grows the hind legs first and then the fore legs. It is now called a froglet————————————

ANS: d-c-e-b-a
Q No.6

How is the caterpillar different from an adult butterfly? Write any three differences.

Caterpillar Butterfly
i)                  The caterpillar has a long, visibly segmented body with many pairs of legs.

ii)                It is the larva stage of butterflies and moths.

iii) It has no wings so it is unable to fly.

iv) It is green.

1.The butterfly has a body composed of a head, thorax and abdomen, two antennae and two eyes.

2.It is a flying insect having four stages in its life.

3.Its wings make it possible for it to fly.

4.It is colourful.

Q No.7

     A number of animals have become extinct. Search the Internet to find out how the following animals disappeared:

red gazelle, Caspian tiger, dodo, dinosaurs



A 1. F 2. E 3. A 4. B 5. C 6. D

B 1. a) two 2. a) gram 3. b) wheat 4. C two cotyledons net-like veins tap root 5. c) cotyledon 6.A one cotyledon parallel veins fibrous 7. a) mono cot 8. b) di cot

C: Answer the Questions:

Q No. 1 Define the following:

a) seed coat:   the outer covering of the seed which protects the internal structure from injury and drying out

b) endosperm:   the plant’s food supply; it surrounds the growing embryo and provides food for it

c) embryo:   a baby plant that grows into a new plant when conditions are suitable

d) angiosperm:   the group of plants having seeds enclosed in their fruits or flowers

e) gymnosperm:   the group of plants having naked seeds, which means that their seeds are not enclosed in their fruits or flowers

Q No.2Below are the diagrams of the internal structure of different stems.

Which diagram shows the stem of a monocot and which one shows the stem
of a dicot? Write a reason for your identification.

A.                       B.

ANS:A stem of dicot plant: the xylem and phloem are very organized inside the stem.

B stem of monocot plant: the xylem and phloem are scattered throughout the stem.

Q No.3Which of the following is a leaf of a dicot plant and which is a leaf of a monocot plant? Give reasons for your choice.
ANS:A leaf of a monocot: has parallel venation

B leaf of a dicot: has net venation

Q No.4Compare between dicot and monocot in the given table:
Seeds Leaves Flowers Stems Roots
MONOCOT one seed leaf parallel venation petals in multiples of three vascular bundles scattered throughout the stem fibrous roots
DICOT two seed leaves net venation petals in multiples of four or five vascular bundles are very organized tap roots





























U: 10                     SOIL EX- (P: 56-57)

A:Write T for the statements which are true and F for the ones which are false.

B 1. topsoil 2. clay 3. subsoil 4. sand 5. clay 6. Roots

C 1. c 2. c 3. c 4. c 5. a 6. c

D: Answer the Questions:

Q No. 1What is soil and what is it composed of?
ANS: Soil is the topmost layer of the surface of the Earth.

It is composed of four things: water, air, particles of minerals and organic matter.

Q No.2Name the layers of soil in the sequence in which they are present on land.




Q No.3Write two ways in which soil is important for living things.
ANS:Soil is important for living things as plants and crops grow in the soil. It is a place of shelter for small animals and insects.
Q No.4How do small animals help the soil?
ANS: Small animals help to aerate and enrich the soil.


Name:                           Class:5th        2nd Sem2014

U: 11                 MATTER         EX- (P:65-67 )

A 1. F 2. E 3. G 4. H 5. A 6. I 7. B 8. C 9. D

B 1. matter 2. mass 3. definite 4. volume 5. shape, volume

  1. regular 7. sublimation 8. condensation 9. physical 10. solid

C 1. a 2. c 3. a 4. a 5. b 6. b 7. b

D 1. A physical change of matter means a temporary

D: Answer the Questions:

Q No. 1

What do you understand by physical change? Give three examples of physical changes taking place in your environment.


A physical change of matter means a temporary change. In these changes only the state of the matter changes. No new substance is formed. It can easily be reversed to its original state.

Some examples:

a) boiling milk / water

b) cutting or crumpling paper or cloth

c) melting ice cream

Q No.2

Draw diagrams to show the arrangement of particles in a solid, a liquid and a gas.


Ensure that the distances between the particles, and their movement is correctly shown in the diagrams.

Q No.3

Briefly explain the water cycle with the help of a clearly-labelled diagram


The water cycle

The water cycle is a reversible change in the states of matter.

a)     Water evaporates into the air. The Sun heats up water on land, in rivers, seas and oceans and turns it into water vapour. The water vapour rises into the air.

b)    Water vapour condenses into clouds. It cools down and changes back into tiny drops of liquid water, forming clouds.

c)     The clouds become heavy with water, which falls back to the Earth as rain or snow.

d)     Rain water runs over the land and collects in lakes and rivers which take it back to the seas. The water cycle starts all over again.

Q No.4

Compare the characteristics of solids, liquids and qoses in the given table.


Phase Solid Liquid Gas
1.Distance between particles tightly packed loosely arranged apart from each other
2.Motion of particles vibrate about a fixed position slide on each other high speed
3.Energy of particles less energy more than solid and less than gas high
4.Volume definite definite not definite
5.Shape definite not definite not definite
6.Two examples stone, block of wood oil, water oxygen, carbon dioxide

U: 12 THE SUN & THE MOON     EX- (P: 74-75)                          

A1 False 2. True    3. False  4. False  5. True

  1. False  7. False    8. False  9. False  10. True

B 1-phases 2. waxing 3. waning 4. waxing gibbous 5. helium 6. nuclear reactions 7. 6000 8. solar energy 9. Milky Way 10. seasons

C: Answer the Questions:

Q No.1

Explain the effects on Earth of the a) Sun’s gravity       b) Moon’s gravity


a) Sun’s gravity

The pull of the Sun’s gravity is so strong that it keeps all of the planets orbiting around it. The Sun holds the Earth in its orbit.

b) Moon’s gravity

The Moon’s gravity causes the oceans to rise to high tides and fall to low tides.

Q No.2

Write any three differences between the Sun and the Moon.

Q No.3

Draw and colour a picture of the Sun in your notebook and compile a fact file on it.

Q No.4

What is a galaxy? Draw the Milky Way galaxy. Research and write three facts about it.


A galaxy is made of millions of stars, dust and gas.


1-      Galaxy is a collection of stars, gas, and dust bound together by gravity.

2-      The smallest galaxies may contain only a few hundred thousand stars, while the largest galaxies have thousands of billions of stars.

3-      The Milky Way galaxy contains our solar system.

4-      The basic types of galaxy – spiral, barred, elliptical, irregular; types vs. distance .

Q No.5

How many days does the Moon take to complete one revolution round the Earth? a) 29     b) 29     c)30    What is this period called?


b) about twenty-nine days. This period is called a lunar month.

U: 13 AIR          EX- (P:81-82 )

A 1. atmosphere 2. burning 3. carbon dioxide 4. space 5. water vapour      6. wind 7. compressed 8. hot 9. nitrogen 10. stratosphere

B1. b nitrogen 2. c argon 3. a carbon dioxide 4. c oxygen 5. a it has mass and occupies space 6. c 0.03% 7. a 20.94% 8. c variable 9. c nitrogen

C: Answer the Questions:

Q No.1

a)       Explain what is meant by the atmosphere.

b)List the different layers of the atmosphere.


a) The Earth is surrounded by a thin layer of air called the atmosphere.

b) The atmosphere is made up of several layers. These are the:

1. troposphere


3. mesosphere

4. thermosphere

5. exosphere

Q No.2

How is carbon dioxide useful?


Carbon dioxide is used by plants to make food.

Q No.3

Why would you expect to find oxygen cylinders in hospitals?


Oxygen cylinders are used in hospitals for patients who have difficulty in breathing

Q No.4

List any five uses of moving air.


Uses of moving air

i) Moving air is used as a form of energy. It supports birds, gliders and airplanes.

ii) Sailing boats use the power of moving air to move across the water.

iii) Windmills use the force of wind to draw up water for the fields or to generate electricity.

iv) Moving air speeds up the drying of the washing.

v) We use moving air from a fan to cool ourselves.

Q No.5

List any three uses of compressed air.


Uses of compressed air

i) Compressed air is used to inflate balloons.

ii) Compressed air is used to inflate the tyres of bicycles, rubber tubes, cars and aircraft.

iii) It is used to fill oxygen cylinders.

iv) It is used to inflate balls.

v) It is used to create fizz in soft drinks.

Q No.6

a) What is the ozone layer?

b) How is it helpful to life on Earth?


a) The ozone layer is one of the most important layers of the atmosphere. It is found in the stratosphere.

b) The ozone layer blocks and absorbs most of the harmful rays of the Sun, preventing them from reaching the Earth. In other words, the ozone layer acts like a protective blanket for the Earth.


A 1. True 2. False 3. False 4. False 5. True 6. False

  1. True 8. False 9. False 10. True

B: Answer the Questions:

Q No.1

Define the following terms. (a)environment  (b)pollution


a) The environment is everything that is around us, wherever we happen to be.

b) The contamination of air, water, or soil by substances that are harmful to living things is known as pollution.

Q No.2

List any five items which you throw away or waste at home.



fruit skins,

plastic bottles,

shopping bags etc.

Q No.3

Copy and complete the following table in your notebook.


Type of pollution Causes Effects Ways to reduce
Land chemical waste produced by factories, human sewage, litter, overuse of pesticides and herbicides, construction debris Toxic chemicals are transferred from one living thing to another. Dispose of the waste properly; recycle paper, plastic, glass bottles, cardboard and aluminium cans.
Air smoke from factory chimneys, vehicle exhaust fumes, burning of fossil fuels, natural disasters like wild fires, volcanoes, etc. breathing disorders such as asthma and bronchitis; depletion of protective layer in the atmosphere known as ozone When possible use public transport or walk or ride a bicycle; use CNG rather than petrol in cars.
Water oil spills, untreated human sewage, use of pesticides, herbicides and fertilizers by farmers Use of polluted water may cause infectious diseases like cholera and typhoid; oil spills cause immense damage to sea life. Do not throw litter into rivers, lakes and oceans.

U: 15 ELECTRICITY           EX- (P: 94-97)

A1. B charged object 2. F proton 3. E electron 4. A neutron      5. D electric current 6. C neutron


  1. electric current 2. static 3. negative(-) to positive ( +) 4. conductors 5. insulators 6. atoms 7. static 8. neutral 9. positively 10. negatively

C 1. b 2. b 3. a 4. b 5. a 6. c 7. b 8. a 9. c 10. b

D 1. True 2. False 3. False 4. True 5. True 6. False 7. False

E: Answer the Questions:

Q No.1

Define electric current.


The flow of electrons in an atom from the negative to the positive terminal is called electric current.

Q No.2

Describe in your own words how electric current passes through a wire.


In some materials the electrons are free to move. When such materials are connected to an electricity source these free electrons become energized. They start moving from one end of the material, the other, passing from atom to atom.

Q No.3

What is static electricity? Give two examples of static electricity that you have experienced.


When an atom comes into contact with another atom, electrons may jump from one atom to another. When this happens, the atom ends up having more electrons than protons. This atom becomes negatively charged, and the atom which gains electrons becomes positively charged. This imbalance of positive and negative charges is called static electricity.

Examples of static electricity:

Q No.4

What is an atom?


All matter is made up of tiny particles called atoms.

Q No.5

What are the subatomic particles of an atom? How are they different from each other?


An atom is made up of very tiny particles known as subatomic particles. These are protons, electrons, and neutrons.

Differences between particles:

Protons have positive charge and are found in the centre of the atom.

     Neutrons have no charge at all. They are also found in the centre of the atom. Protons and neutrons together make up the nucleus of an atom.

   Electrons have a negative charge and keep moving round the nucleus of the atom.

Q No.6

Draw a neat and clearly-labelled diagram of an atom.


On Page:91

Q No.7

In what ways do we see electricity in nature?


We see electricity in nature in the form of sparks and lightning.

Q No.8

Why is an insulator unable to conduct electric current, while a conductor can?


An insulator cannot conduct electricity because it does not have free electrons to move from one end to another end of the material. Conductors have free electrons to move, so they can conduct electricity.

U: 16 ELECTROMAGNETS     EX- (P: 103)

A 1. True 2. False 3. False 4. True 5. False

   B 1. magnet 2. magnetic field 3. attract, repel 4. demagnetization 5.electromagnet

C: Answer the Questions:

Q No.1

Define the following terms.

a)        magnetic and non-magnetic material (b)magnetic field


a) Materials which are attracted by a magnet are called magnetic materials.

Materials which are not attracted by a magnet are called non-magnetic materials.

b) The magnetic field is an area around the magnet where its force of attraction can be felt most strongly.

Q No.2

What is meant by demagnetization? Explain any three ways to demagnetize a magnet


Demagnetization is a method or process by which a magnet loses its magnetism or force of attraction. This can happen if magnets are:

1. dropped repeatedly

2. heated

3. hammered

4. kept close to each other when not in use.

Q No.3

What are electromagnets?


Electricity can be used to convert a magnetic material into a magnet. Such magnets are called electromagnets.

Q No.4

How can you turn an iron nail into a magnet?


An iron nail can be turned into a magnet by passing an electric current through it.

Q No.5

How can you increase the strength of an electromagnet?


The strength of an electromagnet can be increased by increasing the number of coils around the iron nail, or by increasing the flow of current in the wire.

Q No.6

Write any three uses of electromagnets in daily life.


Three uses of electromagnets in daily life are:

• in the speakers of TVs, radios, tape recorders.

• in doorbells and generators

• in scrap yards to separate metals.

Q No.7

A special toy train is able to float above its track. Use your knowledge about magnetic repulsion to explain how it is done.


If this train is able to float above the track, it means the track and the toy train contain magnets underneath the train and on the surface of the track. These magnets have been positioned so that the bottom of the train and the surface of the track both face the same poles.

U: 17 FORCES    EX- (P: 103)

A 1. B 2. C 3. D 4. A

B1. push, pull 2. Newton meter or spring balance 3. newton 4. friction 5. gravity 6. repels 7. mass 8. force 9. Isaac Newton 10. heat

C 1. True 2. False 3. True 4. False 5. True 6. True

D: Answer the Questions:

Q No.1

Compare weight and mass with the help of a table of comparison.

Weight           mass


Weight               mass

a) 1.The gravitational force acting on an object is known as weight.

b) 2.SI U is the newton.

c) 3.Weight is affected by the force of gravity.

a-The measure of the amount of matter in an object is known as mass.

b-Its SI U is the kilogramme.

c-Mass is not affected by the force of gravity.

Q No.2

Define the following with examples.    a) force            b) gravity

ANS:a) Force is a push or pull exerted by one object on another.

b) The force of attraction between two objects is known as gravity.

Q No.3

Which of the following involve forces and which do not?

a) opening a door                         b) turning a key in the lock

c) smelling food cooking              d) putting thread into needle

e) looking at a picture             f) hitting a key on the computer keyboard


a) opening a door

b) turning a key in the lock

d) putting thread into needle

f) hitting a key on the computer keyboard


c) smelling food cooking

e) looking at a picture

Q No.4

What holds the Earth as it orbits the Sun?

ANS: The Sun’s gravitational force holds the Earth in its own orbit as it revolves around the Sun.
Q No.5

Explain why the weight of a person or object decreases on the Moon.

ANS: When a person moves from the Earth to the Moon, his weight decreases because the Moon is smaller than the Earth, so it has less gravity and exerts less force.
Q No.6

What is the relationship between surface type and the amount of friction?

ANS:Rough surfaces have more friction than smooth, plain surfaces.
Q No.7

a) State any two situations where friction can be helpful.

b)       State any two situations where friction can be a problem. How can
these problems be solved?


a) Friction between our shoes and the ground helps to walk without slipping.

Friction between the pencil and paper helps us to write.

b)                                 Heat produced by friction can become a problem in machinery.


It can be reduced by oiling the moving parts. The friction created by a rough surface can become a problem when an object is required to slide easily.

In this case the friction can be reduced by making the surface smoother.

Q No.8

How would life be different if there was no friction at all?

List three things which would be difficult to do, and three things which would become easier?

ANS: How things would be difficult:

• If there were no friction at all we would not be able to walk on the ground.

• There would be traffic accidents due to the absence of friction between the car tyres and the surface of the road.

• We would not be able to write anything.

How things would be easy:

• Machinery would work more smoothly and would last longer if there were no friction at all.

• Our shoes would never wear out if there were no friction.

• Anything we would like to slide easily would work better without friction.


U: 18 SOUND         EX- (P: 118-119)

A 1. C 2. D 3. A 4. B

B 1. vacuum 2. frequency 3. hertz 4. wave 5. 20 and 16000 Hz

  1. medium 7. solid 8. gas 9. echo 10. 102,000 Hz

C 1. both a & b 2. c 3. b 4. b 5. a

D: Answer the Questions:

Q No.1

Define the following terms.

a) sound                              b) vibration

c) sound wave             d) frequency


a) Sound is a form of energy that is produced by vibrations.

b) The to and fro movement of an object is known as vibration.

c) The vibrations passing from molecule to molecule are called sound waves.

d) The number of vibrations per second is called the frequency.

Q No.2

In which part of the ear are there fine hair cells which detect sounds?


Inside the ear, the cochlea has tiny hair that detects sound waves.

Q No.3

Explain in your own words how sounds are made and how they travel through the air.



Sound is also a form of energy. It is produced by vibrations and travels in waves.

When an object hits the surface of water, the waves travel outward in a circle. Sound waves too travel outward in circles, but we cannot see them.

Q No.4

In what conditions do sounds echo?

ANS: An echo is produced when sound waves hit a hard surface. If a sound is made in a large empty room, it echoes. If there are many objects around the sound source, it will not echo because the sound energy will be absorbed by these objects.
Q No.5

In terms of their waves, how are noise and musical notes different from each other?

ANS: Both noise and musical notes are sounds. They are different because noise is disturbing while musical notes provide pleasure to the listener.
Q No.6

Can sound travel in a vacuum? Explain your answer.

ANS:Sound needs a medium to travel through. It cannot travel in a vacuum because there are no molecules to pass on the vibrations.

U: 19 LIGHT          EX- (P: 123-124)

   A1. A pinhole camera has no lens. It has a pinhole at one end and a paper screen at the other end. A very tiny hole at one end of the box is used as a lens. The smaller the hole, the sharper the image. The image produced by a pinhole camera is upside down and reversed.

  1. Light is refracted when it bends, and is reflected when it bounces back.

B 1. a 2. b 3. a 4. c

C 1. A pinhole camera is a very simple camera

D: Answer the Questions

Q No.1

How do we know that light travels in straight lines?

ANS: A pinhole camera is a very simple camera with no lens and a single, small hole. Simply explained, it is a light-proof box with a small hole on one side.
Q No.2

Describe one property of light used by the pinhole camera.

ANS: Light travels in straight lines. This is the property that is applied in a pinhole camera.
Q No.3

What happens when you shine white light through a prism?

ANS: When we shine light through a prism, it scatters into different colours. These colours are known as a spectrum or rainbow.
Q No.4

Write a few sentences about the scientific achievements of Ibn al Haytham.

ANS: Ibn al Haytham was a great Muslim physicist.

He was the first scientist to study the properties of light.

He studied dispersion of light, shadow formation, and eclipses. The early foundations of the camera and the microscope were laid by this great scientist.

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