Q No. 1 Write proper term/ word against each statement.

Ans: (i- organ) (ii-nucleus )   (iii- multi cellular ) (iv- tissue ) (v- cell wall ) (vi- microscope )


Q No.2 Circle the letter of the best answers.

Ans: (i-c ) (ii- b) (iii- b ) (iv- a )   (v- d )


Q No.iDescribe parts and functioning of a light microscope?

It is an instrument to see very small things that cannot be seen with naked eye. We can view an object up to 1500 times bigger than its original size. These microscopes use light to show the images.


It has base, an arm, a tube a stage and two adjustment screws.

EYEPIECE: The end of the tube through which
we observe an object is’ called an eyepiece.

OBJECTIVE LENS: The lens near the object to be seen is called an objective lens.

     MIRROR: Light is passed through the object from below, using a mirror.

GLASS SLIDE: The object to be seen is placed on a glass slide and then on the stage.

ADJUSTMENT SCREWS: To focus the object clearly in the microscope.’ two adjustment Screws are used.

Q No. iiDescribe the structure of a plant cell? Also draw its labelled diagram?
ANS:a)             A CELL WALL

The outermost covering of a plant cell is called the cell wall. It is absent in-animal cell. It is ‘made of a hard material called cellulose. The cell wall gives support, shape and strength to the cell.


The outermost covering of animal cell is called CELLMEMBRANE. In plant cells the cell membrane is present below the cell wall. The cell membrane controls the movement of materials in and out.


             The most important part of a cell is its nucleus. It controls all the activities of the cell. Therefore, a nucleus is the control centre of the cell.

Q No.iiiWrite a note on the nucleus of a cell?

The most important part of a cell is its nucleus. It controls all the activities of the cell. Therefore, a nucleus is the control centre of the cell.

A thin membrane, called nuclear membrane, surrounds the nucleus. Many thread like structures called chromosomes are present in the nucleus.

Chromosomes pass on the characteristics of the cell to new cells. The number of chromosomes is fixed in every cell. A human cell has 46 chromosomes.

Q No. ivWrite about shoot system of a plant?
ANS:SHOOT SYSTEM                                    

The part of the plant above the ground forms the shoot system.
The shoot consists of stem, leaves, and flowers.

Shoot system performs the functions like;

–transport of water and food,
–preparing food and

— formation of seeds, etc.

Q No. vDefine a cell, a tissue, an organ, an organ system and an organism.

A cell is a structural and functional unit of a living thing or an organism.


A group of cells that perform the same function is called a tissue.


A complete and independent part of a plant or animal that has a specific function is called an organ. An organ is formed by different tissues which work together.


                 A group of organs which work together is called an organ system. Different organ system does different jobs.


               An individual living thing that can carry on the activities of life by means of organs is called an organism.


CH: 2   SENSE ORGANS P: 23-24


Q No. 1 Write proper term/ word against each statement.

Ans: (i- skin) (ii-pupil ) (iii-nostrils ) (iv- auditory nerve ) (v- taste buds )


Q No.2 Circle the letter of the best Ans.

Ans: (i- c) (ii-a ) (iii-c )   (iv- b ) (v- b ) (vi-d   )


Q No.3

Q No. iDescribe the structure of human eye?
ANS:HUMAN EYE: The eye is an organ of sight. They tell us about colours, shapes and movements of objects around us. The human eye consists of an eyeball. The eye is covered with eyelids.

Eyelashes on the eyelids Keep away dust particles. Under the upper eyelids tear glands open.



In the front of eye, the transparent part is called cornea. Light rays enter the eye through the cornea.


Beneath the cornea the coloured portion of the eye is called iris. Have you ever observed brown, blue and hazel etc.


There is a hole in the middle of the iris, known as pupil. This pupil contracts in bright daylight and expands in dim light.


Behind the pupil, a .flexible lens is present. The lens helps the eye to focus light.


The light sensitive portion of the eyeball is called retina. Eye lens forms the image on the retina.


When light hits the retina, its cells make nerve signals. These signals pass along the optic nerve to the brain.

Q No. iiDescribe the structure and function of inner ear?

The last part of the ear is the inner ear. The inner ear is filled with a liquid.

This part of ear has a coiled structure called cochlea. Cochlea:

The cochlea is the actual hearing organ. The cochlea sends signals to the brain through a special nerve called auditory nerve.

Q No.iiiWrite a note on the sense of smell?

It is the sense organ for smelling. It can detect 10,000 different scents and smells.
Structure Our nose is a hollow air passage.


It has two openings called nostrils.

Air Chamber

In each side of the nose is an air chamber.


1. The roof of the nose has lining of nerve cells to sense smell.

2.  When certain odour chemicals present in air enter our nose, they touch the nerve cells.

3.  Nerve cells pass the message to the brain through the olfactory nerve.

4 Our brain tells whether the odour is pleasant or unpleasant.

Q No. ivWhat is the importance of our tongue?

Our tongue is the sense organ of taste.

It helps to detect the flavour of food.

We can detect different tastes with it.

We feel sweet, salty, sour and bitter tastes on different parts of our tongue.

The tip of the tongue has taste buds to detect sweet taste.

The sides of the tongue have taste buds to detect salty and sour tastes.

The back of the tongue has taste buds to detect bitter taste.

Q No. vWrite a note on our sense of touch?

The skin is the largest sense organ in our body. It is the organ of touch. It covers every part of our body. It protects the inner parts of our body.

Sensitive Cells

The skin contains several kinds of sensitive cells that detect pain, pressure, touch, heat and cold.


Our skin has an outer layer and an inner layer.

The outer layer

The outer layer has colour pigment. It protects the skin from harmful rays of the Sun.

The inner layer

The inner layer has blood vessels, nerves, sweat glands and roots of hairs. This layer is the sensitive part of the skin. When we touch something, sensitive cells of the skin receive messages and send them to the brain.





Q No. 1 Write proper term/ word against each statement.

Ans: (i- respiration ) (ii- epiderms )   (iii- photosynthesis ) (iv- chlorophyll ) (v- stomata )


Q No.2 Circle the letter of the best Answer.

Ans: (i-c ) (ii- d) (iii- a ) (iv- d )   (v- b )


Q No.3

Q No. iDescribe the internal structure of leaf.
ANS:Internal Structure of a Leaf

The observation under a powerful microscope reveals that there are three main internal parts of a leaf;


It is the outermost layer of cells. Its upper layer is called upper epidermis. Its lower layer is called the lower epidermis.

Lower epidermis has many stomata. Oxygen, carbon dioxide and water vapours pass through stomata.

2. Mesophyll

It is a layer of soft cells containing chloroplasts. It lies between the epidermal layers of a plant leaf.

A green pigment chlorophyll is present in chloroplasts. Chlorophyll traps light energy. This energy is used in food making process. The food making process takes place in mesophyll.

2.Vascular Bundle

The central part of the mesophyll tissues is made of vascular bundle. Vascular bundle has xylem and phloem tissues.

Xylem tissues carry water from roots to the leaves.

         Phloem tissues carry prepared food to other parts of a plant.

Q No. iiWhich factors are necessary for photosynthesis?


Mesophyll cells’ of leaves contain chloroplasts. A green pigment chlorophyll is present in chloroplasts. Chlorophyll traps
light energy. This energy is used in food making process. The food making process is called photosynthesis. Of the seven colours of light, chlorophyll absorbs blue, orange and red light.

Photosynthesis increases as the light intensity increases.


Plants absorb Carbon dioxide from air. It is an essential component for photosynthesis. The rate of photosynthesis increases with increasing carbon dioxide level.


Normally plants grow well at 25-35°C. Temperatures below O°C and above 40°C are not suitable for plant growth. As a
general rule, when the temperature gets higher, the process of photosynthesis becomes faster.


Water is also an essential element for photosynthesis and it is required in limited amounts.


Chlorophyll is the green material in traps sunlight for photosynthesis. It gives green colour to the leaves. Without
chlorophyll the photosynthesis is impossible.

Q No.iiiProve that the structure of a leaf facilitates the process of photosynthesis?

Structure of Leaf is Well Suited to Photosynthesis.

Structure of green leaves is suitable for photosynthesis.

Therefore, mostly photosynthesis occurs in green leaves.

1.   Most leaves have a flat blade which helps these leaves to absorb maximum light.

2.   Leaves are thin. So carbon dioxide and light reach inner cells easily.

3.   Leaves have large number of stomata in the lower epidermis. Carbon dioxide enters and oxygen and water vapours leave
through these stomata.

4.   Mesophyll cells have thick layer and they make enough food for the plant.

5.   Vascular bundle of the leaf has a network of veins to carry water to photosynthesizing cells and taking glucose away from them.

Q No. ivHow does respiration occur in plants?

A process in plants in which oxygen delivered to tissues or cells of a plant and carbon dioxide and water are given off is
called ‘Respiration’.

This process produces energy in living things. In this process plants use oxygen to break down glucose into water, carbon dioxide and energy.


The equation form of this process is as follows:

Glucose + Oxygenà Carbon dioxide + Water + Energy

Exchange of Gases

Exchange of gases in plants takes place through stomata present in leaves.

This process takes place in the following two different steps:

1)                 Photosynthesis takes place during daytime. This process produces glucose and oxygen. Plants use this glucose and oxygen in respiration and produce carbon dioxide and water. Carbon dioxide and water are used in photosynthesis.

2)             The process of respiration continues all the time.

In this process, plants take in oxygen from the air and gives out carbon dioxide and water.




Q No. 1 Write proper term/ word against each statement.

Ans: (i-biotic) (ii-omnivores)(iii- decomposers)   (iv- parasite ) (v- mutualism ) (vi- prey )


Q No.2 Circle the letter of the best Ans.

Ans: (i-c ) (ii- b) (iii- d ) (iv- a )   (v- d )


Q No.3

Q No. iHow do plants depend upon animals for their needs?

All organisms (plants and animals) interact with each other.
Plants depend upon animals for:

Plants cannot make their food without carbon dioxide gas. All animals release carbon dioxide during respiration. Plants absorb this gas from air.


Animals also help some plants in their pollination. Pollination is a process by which pollens are transferred from the male structure of a plant (such as the anther) to the female structure of a plant (such as the stigma), and plant begins to grow. Animals also help some plants in their pollination.

Q No. iiExplain the abiotic factors of the environment?

Abiotic components means non-living components. They are Light, temperature, soil, air and water.

1)      LIGHT:

Light is a very important abiotic factor of the environment.

1.    Plants prepare food by photosynthesis they need light for this process.

2.    Human beings and most of animals need sunlight for most of their activities.


The Sun maintains temperature of places of our Earth.

1.    Most organisms are active at normal temperature of the Earth.

2.    Other planets are so cold or hot that no life is found there.

3) AIR

Air is an important abiotic factor.

1. Animals and plants respire in the oxygen of air to live alive.

2. Plants also need carbon dioxide from air to make their food.


Soil is an important factor of environment.

1. Plants get water and necessary minerals from soil.

2. Bacteria present in soil provide important compounds to the plants.


1. Water is essential for life in the environment.

2. A large number of plants and animals are found in rainforests.

3.      Many plants such as lily and hydrilla are found in water.

Q No.iiiExplain the following with examples:

(i) Parasitism (ii) Mutualism (iii) Types of consumers


Parasitism is a relationship between two living organisms in which one is harmed and other helped.


A parasite is a living organism that feeds on another living organism.


The living organism on which the parasite feeds is called the host.

Examples: The female mosquito uses our blood or the blood of another animal for food. We are the host and mosquito is a parasite.

2. Mutualism

Mutualism is a relationship in which two living organisms live together and depend on each other.
Mutualism occurs among some plants and animals.

Examples: Termites eat wood. However, they are not able to digest the wood. There is a unicellular organism inside the termites. This unicellular organism is able to digest the wood.


a. Herbivores: Herbivores are the animals that eat only plants.

Examples: Cows, goats, horses, squirrels and butterflies

b. Carnivores: Carnivores are the animals that eat flesh of the herbivores or other animals.
Examples: Cats, dogs, frogs, tigers and snakes

c. Omnivores: Omnivores are the animals that eat both plants and animals.

Examples: Humans, chickens, crows and bears.





Q No. 1 Write proper term/ word against each statement.

Ans:(i-molecules)(ii-elements)(iii-distillation)(iv- chromatography ) (v- sublimation )


Q No.2 Circle the letter of the best Answer.

Ans: (i- a) (ii-c ) (iii- c ) (iv- d )   (v-c )


Q No.3

Q No. iRelate physical properties of metal elements with their uses?

I. State

Most metals are found in solid state. However, mercury (Hg) is found in liquid state. Mercury is filled in thermometers to measure temperature.

ii. Hardness

Most metals are hard solids.

For example, iron is used to make steel. The steel is then used for making rails, girders, surgical instruments and utensils.

iii. Lustre

Freshly cut metals have brilliant shine, called lustre.

For example, aluminium is used for making utensils and picture frames due to its lustre.

Gold and silver are used to make ornaments because of their shine.

iv. Melting and Boiling Points

Metals have high melting and boiling points. Due to this property iron, copper and aluminium are used to make kitchen utensils.

v. Strength and Malleability

Metals are used to make sheets, wires and springs due to their property of strength and malleability.

vi. Conductivity

Metals like copper and aluminum are used in electrical wiring. They have the property to allow the electricity to pass through them. This property is called conductivity.

Q No. iiDefine and explain compounds?
                       When two or more elements combine chemically in a fixed ratio, a compound is formed.

    Example: Water is the compound made of the
elements hydrogen and oxygen.

Hydrogen + Oxygen — Water

1.    There are 109 known elements but there are thousands of compounds.

2.    Elements in a compound can not be separated easily.

3. Properties of elements change when they are combined as compounds.

In case of water, hydrogen and oxygen are colourless gases. They have no smell or taste. Hydrogen burns very quickly in oxygen. Both of these gases combine to form water which is a compound. We can see and taste it.

Q No.iiiWhat do you know about sublimation and distillation?

A process in which a solid on heating, directly changes into gas or vapour state is called sublimation.


1.      We can use this process to separate the two components of a mixture if one component has the property of sublime.

2.      Iodine, ammonium chloride (Noshader camphor and naphthalene have the property of sublime It is also interesting that on cooling, the vapours again return to solid

Solid ↔ Vapours


A method by which two or more liquids D solution are separated by boiling off the liquids with the lower boiling point and condensing in another container is called ‘Distillation’
the components of a mixture have different   boiling points, we can separate these components using this method.

1. Doctors use distilled water for injections.

2. In some countries like Kuwait and Saudi Arabia, sea water is passed through process of distillation to get drinking water.

3. In an oil refinery the method of distillation is used to separate components (petrol, tar, oil, dissolved gases and kerosene oil) of crude oil.

Q No. ivDefine paper chromatography and explain it with the help of an activity?

A set of laboratory techniques used the separation of mixtures is called ‘Chromatography’.

In paper chromatography, special paper is used to separate the coloured components in a mixture.

Chromatography only works If soluble dyes, like in food and pen not dyes in Clothes. The most soluble dyes move faster on a filter paper than less soluble dyes.


You will need: a beaker, a medicine e dropper, a filter paper, solution of a dye or ink


1.   Place a filter paper on the beaker.

2.Put a drop of ink in the middle of the filter paper.

Soon you will see different bands of colour on the filter paper. Each band shows the presence of a different component of the solution.

Q No. vWrite symbols of the following elements:
ANSWER: potassium nitrogen sodium gold mercury silver
K N Na Au Hg Ag


CH: 6   AIR P: 64-65


Q No. 1 Write proper term/ word against each statement.

Ans: (i- atmosphere) (ii- nitrogen) (iii- oxygen ) (iv- carbon dioxide )


Q No.2 Circle the letter of the best Ans.

Ans: (i-b ) (ii- b) (iii-a )   (iv-c ) (v- c )   (vi- d)


Q No.3

Q No. iWhat is the atmosphere? How is air important for us?

Air covers the Earth like a thick blanket. This blanket of air is called the atmosphere. Air is a mixture of gases. Air is present everywhere. Even in water and soil, air is present.
Layers of Air

Many layers of air are present in the atmosphere. Scientists have divided the atmosphere into four layers;

1.Troposphere 2. Stratosphere 3. Mesosphere 4.Thermosphere.                


Air is very important to us:

1.  We breathe in the air. We can’t live without it.

2.  Air is needed for burning.

3.  We pump air into footballs, balloons and tyres of our vehicles.

4.  In our homes, we use air pressure to draw dust into the bag of vacuum cleaner.

5.  Fish and other animals in water use the air dissolved in water for respiration.

6.  Plants use air (carbon dioxide) to make their food.

Q No. iiWrite some uses of oxygen in our daily life.

1.   All the living organisms use oxygen for respiration.

2.  It is essential for burning of wood; coal and natural gas.

3.  It dissolves in water. Due to this property animals and plants breathe in the water.

4.  It is used in welding and cutting of metals.

5.  It is used in paper industry as a bleaching chemical.

6.  Some patients of lungs and heart diseases need oxygen in hospitals.

7.  Mountain climbers, sea divers and astronauts carry oxygen· in cylinders for breathing.

8.  Liquid oxygen is used in rockets as fuel during their space journeys.

9.  Oxygen in the form of ozone layer protects us from harmful ultraviolet radiation of the Sun.

Q No.iiiWrite some properties of carbon dioxide.

The amount of carbon dioxide in air is less than one percent.


1. It is a colourless gas.

2. It has no smell but a sour taste.

3.    It is slightly soluble in water but it: solubility increases under high pressure.

4.    It is heavier than air:

5. It can turn lime water milky.

6.    It does not burn.

7.    It also does not support the burning.




Q No. 1 Write proper term/ word against each statement.

Ans: (i-solute ) (ii- saturated) (iii- solvent ) (iv- dilute )


Q No.2 Circle the letter of the best Ans.

Ans: (i-c ) (ii- a) (iii-a )   (iv-b ) (v- d )


Q No. iDescribe the particle model of solution.

We know that matter consists of tiny particles. These particles show special behaviour. A particle model explains the behaviour of particles of matter.

1.        The matter is made of tiny particles.

2.        Particles of matter are in constant motion

3.        There are forces of attraction between particles.

There are spaces between particles. On heating, the particles start moving faster.

Q No. iiProve that water is a universal solvent?
ANS:Most of the things dissolve in water easily. We can say that water is a very good solvent.

1-   Sugar, rock salt and sodium bicarbonate (meetha soda), etc. dissolve in water.

2-       Milk alcohol, lemon juice, vinegar and apple juice dissolve in water.

3-       The food we eat forms a solution in the body and then absorbs in the blood.

4-       Many harmful substances are produced in our body. These substances.
dissolve in water and excrete as urine and perspiration.

5-       Plants absorb minerals from -the soil that are dissolved in water.

6-       Oxygen gas dissolves in water. It keeps aquatic animals alive.

7-       Carbon dioxide gas also dissolves in water. Aquatic plants use this dissolved carbon dioxide to make food.

Therefore, we can say that water is not just a solvent but a universal solvent.

Q No.iiiWhat is solubility? How does temperature affect the solubility?

The amount of solute in grams dissolved in 100 grams of the solvent at a ‘given temperature is called its solubility at that temperature. The solubility of n solute increases with increase in temperature.


1.We can dissolve 24 grams of crystals of blue copper sulphate in 100 grams of water at room temperature (25°C) to make saturated solution.

2.    At 60vC,60 grams of copper sulphate will dissolve to make saturated solution

2.In other words we can say that the solubility of copper sulphate is 24 grams at 25°C and 60 grams at 60°C.

2.    We can also conclude that the solubility of a solute increases with increase in temperature.


1.    Take 100 grams of water in a beaker.

2.Make a saturated solution of sodium chloride(table salt) at room temperature.

3.Start heating the solution on a spirit lamp.

3.         Now add some more salt in the solution and stir it.


You will see that more amount of salt is dissolved in this hot solution.

Q No. ivCompare the properties of solutions and suspensions.
1.Particles of solute particles of solute do not settle out. 1.Particles of solute settle down on standing.
2.Particles pass through ordinary filter paper. 2.Particles can be separated by ordinary filter paper.
3.Light rays do not scatter on passing through the solution. 3.Light rays scatter on passing through the solution.
Q No. vDefine the solvent, solute and saturated solution?

              A component of a solution which is in less amount is called solute.


The substance in which solute is dissolved is called solvent. The solvent is always more in quantity than a solute.


               A solution in which the solvent can not dissolve any more solute at a particular temperature is called a saturated solution.



CH: 8   ENERGY & ITS FORMS P: 87-88


Q No. 1 Write proper term/ word against each statement.

Ans: (i- conservation of energy) (ii- electrical energy ) (iii- biogas ) (iv- potential energy ) (v- light energy )


Q No.2 Circle the letter of the best Ans.

Ans: (i- b) (ii-d ) (iii-d )   (iv-c ) (v- b )


Q No. iWhat is the difference between potential and kinetic energy? Give two examples?

Energy that is stored in an object due to change in its position is called ‘Potential’ energy’. It is written as P.E.


1.A brick ‘on the ground cannot do any work. But when we raise the same brick, energy is stored in it. The brick can do work due to the potential energy.

2.  The energy in the wound up spring of a toy car is potential energy. This energy can cause the toy car to move.


Energy in a body due to its motion is called kinetic energy. A moving bus and running tap water possess kinetic energy. It is written as K.E.


The amount of kinetic energy depends on the mass of the object and its speed. A train has more kinetic energy than a car moving at the same speed.


1.    Moving objects have kinetic energy. The moving air or wind has kinetic energy. It can move leaves and twigs of trees.

2.Flowing water in a river can move things in it. It has kinetic energy.

Q No. iiDefine and explain the “law of conservation of energy“?
Energy cannot be made nor it can be destroyed but energy can be changed from one form to another.


1.      When the ball stops for a moment at the highest point in its swing, it has no kinetic energy; the energy is all potential.

2.      When it comes down at the lowest point on its swing, its speed is greatest. Here the pendulum has no’ potential energy. The energy is all kinetic.

3.      The pendulum keeps swinging, changing the forms of energy. But the total amount of energy remains constant.

4.      When after along time the pendulum stops its swinging, what happens to its energy? This energy is not lost.

According to the law of conservation of energy, the energy cannot be made or destroyed. It simply changes its form.

In pendulum in each swing, very small amount of its energy changes to heat energy which increases the temperature of the string and the ball. Heat spreads in the atmosphere.

Q No.iiiDescribe at least three renewable sources of energy ?
ANS:Some important forms of energy which are renewable and do not add pollution in the atmosphere.


The kinetic energy of flowing water is changed into the electrical energy, called hydro-electric energy.

Dams are built to get this energy because water required for It is easily available.


Wind is kinetic energy. A windmill is machine which has blades. They blades move by the energy of wind.

A wind farm (consists of about 100 wind mills) is used to generate electricity in great amount.

Wind energy is easily available without any cost.


Biogas is a mixture of such gases which ate formed by the decaying of animal wastes, and mix with water.

Biogas-plant is used to produce biogas, which can be used as a fuel in homes.

The remaining material is used as fertilizer.
It is called gobar gas-plant.

Biogas is cheap as compared to other fuels.


Sun is the ultimate source of energy on Earth.

The solar energy can be changed into electricity with the help of solar cells. Solar energy is an effective renewable energy source in Pakistan.


The winds blow over the surface of the sea, and cause tides in it. These tides can be used to generate electricity.

Like winds the energy from sea tides is also free of cost.

Q No. ivWrite a note on “energy transfer In an environment”?
ANS:Green plants use sunlight to grow and make food. This solar energy is stored in the form of chemical energy of food. Animals and human beings eat the food prepared by the plants.


1-      In living things, the chemical energy of food transfers to their bodies.

2-      The bodies of animals and human beings change the chemical energy of food to the kinds of energy they need.

3-      Heat energy and kinetic energy then dissipate in atmosphere.


Similarly, solar energy causes wind energy, sea tides energy and many other forms of energy.

All these energies change their form and at the end, dissipate in atmosphere.




Q No. 1 Write proper term/ word against each statement.

Ans: (i-simple machine ) (ii- gear train)   (iii- pulley ) (iv- gear ) (v- rear gear )


Q No.2 Circle the letter of the best Ans.

Ans: (i-b ) (ii- d) (iii-b )   (iv-d ) (v-a   ) (vi-a )


Q No. iWrite some uses of a wheel and axle in our daily life?
Wheel and axle help to lift a heavy load, to increase the speed, to push something and to turn direction of movement of something.

a.      To Lift a Heavy load

To lift a heavy load, we apply force on the wheel to turn the axle.

b.      To increase the Speed

To increase the speed, we apply force on the axle to turn the wheel.

c.       To Push Something

A screwdriver is an example of wheel and axle. The broad part of the screwdriver works as a wheel. The narrow part of it acts as the axle. A small force on wheel provides a bigger force at the axle to push, the screw to the wood.

d.      Turn Direction of Movement

The steering wheel of motor vehicles is also an example of wheel and axle. A small force on steering wheel provides a big force to the axle that easily turns the wheels of the vehicle.

Q No. iiDescribe two kinds of pulleys and their working?

1. A fixed pulley is used to change the direction of applied force.

2. The axle of this pulley is fixed with some support.

3. The load is tied on one end of the rope which is passing over the pulley.

4. The force is applied on the other end of the rope to lift the load


1. A moveable pulley does not change the direction of a force. The applied force and the load move in the same direction.

2. This kind of pulley has a hook to tie the load.

3. The moveable pulley moves together with the load.

4. In this kind, the rope is attached to some support while pulley moves.

Q No.iiiDefine a gear and write its characteristics?

A gear is also a modification of the wheel and axle.


               Gear wheel has teeth around it.

The teeth of one gear usually fit into the teeth of another gear.

Q No. ivWrite briefly about the working of a hand drill and a bicycle?

A hand-drill is used to make holes in wood. A hand-drill consists of two mutually perpendicular gears.

     Working: When its larger gear is rotated in a vertical
plane, the smaller gear linked with it rotates very fast in the horizontal plane.


Your bicycle moves with the help of gears. Two gears are linked with each other by a chain. The chain makes it possible for the small gear to move in the same direction as that of the big gear.

The front gear: The front gear is a large wheel with teeth in which pedal is fitted.

The rear gear: The rear gear is a small toothed wheel which’ is present in the rear wheel of the bicycle.

Working: When you pedal the bicycle, you turn the big gear. The big gear turns the chain, which
turns, the rear small gear. When this small gear turns, the bicycle moves forward.




Q No. 1 Write proper term/ word against each statement.

Ans: (i- reflection) (ii- microscope )   (iii- cocave ) (iv-   law of reflection)


Q No.2 Circle the letter of the best Ans.

Ans: (i-a ) (ii-d ) (iii- a ) (iv-c   ) (v- c ) (vi-c   )


Q No. iDefine the transmission, absorption and reflection of light?
ANS:i)                    TRANSMISSION

When light falls on transparent objects, it is transmitted, (passes through) to the other side.


When light falls on rough opaque (semi-transparent) objects, most part of light is absorbed and changed ‘into heat energy, Black surface absorbs most of the light, than white.


When light falls on the smooth shiny surface, it bounces off on a specific angle. This IS called reflection of light.

Q No. iiProve the laws of reflection through an activity?

1.      Fix a white paper on a drawing board using the drawing pins.

2.      Place a mirror strip AB (fixed in a stand) on the paper.

3.      Fix two common pins Q and R before the mirror in a line.

4.      See the images of the pins in the mirror and fix two more common pins Sand T in such a way that images of pins Q and pins Sand T lie on the same straight line.

5.      Join the points Q, R, S, and T with the A on point P. Draw a perpendicular line on P. It is normal.

6.      Observe the angle of incidence QPN the incident ray QR forms with the normal all the angle of reflection NPT that reflection
ray ST forms with the normal.

Q No.iiiDraw a ray diagram for light reflected from a plane mirror?
ANS:Ray Diagram For Light reflection From a Plane Mirror

1. Take a sheet of white paper and fix it on drawing board.

2. Draw a line MR on the sheet.

3. Put a plane mirror vertically along the light.

4. Now fix a pin 0, serving as the object before the mirror.

5. View the image I of pin 0 from left side of the object pin.

6.Stick two pins P and 0 in such a way that both of these pins and image I lie in the straight line.

7.Now view the image from the right of the pin 0 and stick two pins Sand T in the same way.

8.Remove all the pins and put cross (x) to mark the pin holes.

9.Draw lines PO and ST beyond the mirror line MR till both lines cross each other.
10. Draw a vertical line from 0 to I which meets MR on N.

11. Also join 0 to the points A and B where lines PO and ST meet the line MR.

12. Measure ON and IN. ON is the distance of object from the mirror and IN is the distance of image from the mirror. Both
will be equal.

Q No. ivHow does multiple reflection occur in a kaleidoscope?

1.The plate of ground glass throws the reflections in different directions. It makes a beautiful design.

2.When the viewer turns the kaleidoscope, the coloured pieces shift position and the reflected patterns change.

3.The constantly changing patterns are formed by the multiple reflections of the loose coloured pieces through mirrors.

QUETION No. vDescribe in detail the image formation in a concave mirror?

When light rays strike a concave mirror parallel to its principal axis, after reflection they pass through a common point in front of the mirror. This common point is called the principal focus. It is denoted by ‘F’.

A concave mirror has an original principal focus ‘F’. That is why it can form real images on a screen.




Q No. 1 Write proper term/ word against each statement.

Ans: (i-solids ) (ii-gas ) (iii- auditory nerve ) (iv- vibrations )


Q No.2 Circle the letter of the best Ans.

Ans: (i- a) (ii-a ) (iii-d )   (iv-d ) (v- c )


Q No. iProve that sound is a form of energy?

1.  Fix one end of the meter rod on the edge of the table with the help of screw.

2.  Press the free end of the meter rod gently. It will vibrate slowly and will produce a soft sound.

3.  Now push the ruler farther down and release. A louder sound is produced with a higher number of vibrations.

4.  Whenever work is done on an object, energy is given to it. In this case the energy of your hand produces vibrations in- the ruler. The ruler produces sound energy in exchange of your energy.


Energy must always be added to an object to produce sound.

Q No. iiHow does sound travel?
ANS:         How Does Sound Travel?

When someone calls us from a distance, we hear the sound. It mean sound travels.

1.      Sound needs a medium to travel all the time. The medium may be gas (air), liquid (water) or solid (mental).

2.      Sound is a form of energy that spreads from its source in all directions. It is only possible when the vibrating particles hit each other and pass on the vibrations as sound. That is why sound energy needs a medium for
its propagation.

Sound energy cannot travel in vacuum due to the absence of any particles.

3.      Sound also loses energy as it travels from one place to the other. A loud sound dies off after travelling for some distance.

For example, when your friend goes away from you, sometimes your call does not reach him.

Q No.iiiHow do we hear sound?

1.    The outer part (pinna) of the human ear directs sounds into the ear canal.

2.    Inside the ear canal, the sound waves the eardrum. The sound waves make eardrum vibrate.

3.    The eardrum causes three tiny bones in the middle ear to vibrate. Because of the shapes, the bones are named the
hammer, the stirrup, and the anvil.

4.       Then the vibrations move into the cochlea in the inner ear.

5.The cochlea is a snail-shaped organ which is filled with a liquid. When the liquid in the cochlea starts to vibrate, ‘tiny hairs in the cochlea move. They convert the vibrations into signals.

6.These signals of sound travel along the auditory nerve to the brain.



CH: 12   SPACE & SATELLITES P: 130-131


Q No. 1 Write proper term/ word against each statement.

Ans: (i-1957 ) (ii-global positioning )   (iii- ceres ) (iv- comet )


Q No.2 Circle the letter of the best Ans.

Ans: (i- c) (ii- d) (iii-d )   (iv- c ) (v- b ) (vi- c )


Q No.3

Q No. iWrite a detailed note on comets?

A comet is a large ball of ice and dust that orbits the Sun. Comets move around the Sun in an elliptical path. They take a very long time to complete their one orbit around the Sun.


Comets probably come from the far, outer edges of the solar system. They are only seen when they come close to the Sun.

A comet has three parts: a head, coma and a tail.

1. Head

The head is made of ice, particles of rocks and gases. The heads of most comets are only a few kilometres wide.

2. Coma

When a comet comes near the Sun, gases escape from its head due to the heat of the
Sun. A large, fuzzy, circular cloud around the head of a comet is called the coma.

3. Tail

During orbiting near the Sun, a long tail gases and dust particles is formed behind the comet. This tail can be millions of
kilometres long. The. tail of a comet points away from the Sun. Comets far away fro the Sun bear no tail. Most of the time comets remain far away from the Sun.

Q No. iiWhat do you know about asteroids and meteors?
ANS:ASTEROIDS:An asteroid is a piece of rock that orb the Sun between Mars and Jupiter. The astronomers have discovered thousands asteroids. Asteroids .are made of rock, metal or minerals.

Most of the asteroids orbit the Sun, between Mars and Jupiter in a wide band This band is called the aster belt. The asteroid belt is about 15 hundred thousand kilometres wide. Shapes and sizes of Asteroids
Asteroids come in all shapes and sizes.
Diameters of Asteroids
Some asteroids have diameter up to 1,000 kilometres but some are very small in diameter.


Two asteroids are seen from the Earth without the help of a telescope. These are Ceres and Vesta.


Ceres is the largest asteroid ever 1 is covered. Its diameter is about 33 kilometres.


Vesta is half the size of Ceres. Some astronomers suggest that the asteroids may be the pieces of our solar system that never formed a planet.


Most asteroids complete their one orbit round the Sun in about five Earth years.

METEOR   A meteoroid when enters the atmosphere our Earth, it is called a meteor. A meteor stray particle which Comes from the asteroid belt and enters the atmosphere of Earth.

A shooting star, falling star or fireball   

Due to the friction of air, meteors get fire and a trail of light is seen. Some people call falling stars, shooting stars, or fire balls, We can view 20 t o 30 meteors on a clear night.

Most meteors entering our atmosphere burn up 50 to 100 kilometres above the surface of the Earth. It adds tons of dust into our atmosphere every day.

Q No.iiiWhat are the key milestones in space technology?

Here is a look at some of the key milestones in space technology.

October 4, 1957: Soviet Union launches Sputnik I.

January31,1958: United States launches   Explorer 1.

April 12,1961: Yuri Gagarin becomes the first human to enter space and return safely.

July 16, 1969: Launch of Apollo 11. It puts first man on the Moon.

May 14, 1973: United States Launches Its first space station, the Skylab.

June 18, 1983: Sally Ride becomes first American woman in space.

February 19, 1986: Mir space station   launches,

September 30, 2003: First privately owned spaceship launches.
August 4, 2907: Phoenix Lander launches on Mars.

Q No. ivWrite a short a note on any three artificial satellites?

On October 4, 1957, Russia sent the world’s first artificial
satellite, Sputnik – 1 into space. The, name comes from a
Russian word for “travelling companion of the world”.

It weighed just 83 kg. It carried a thermometer and two radio transmitters which sent information about the atmosphere to the Earth. Its two transmitters only functioned for 21 days.

After 57 days in orbit, it was destroyed.

2.Explorer 1

Explorer 1 was the first satellite launched by the United States of America. It was sent into space on January 31, 1958.

It weighed only 14 kg. Explorer 1 sent information about the radiation environment in Earth’s orbit.

3.Geostationary Satellites

Geostationary satellites’ move at a height of about 36,000 km above the Earth. At this height, they move around the Earth at the same speed as the Earth moves around its axis. This satellite seems to be stationary.
They are used as communication satellites. Pakistan has
launched its first geo stationary satellite, PAKSAT – lR on August 11, 2011.




  • Ahmed

    this very good website this website helps me in my exams

  • Ahmed
    December 14, 2018 at 3:30 pm
    That is nice this website helped me in my exams all answers are correct

    again and again thanks

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