General Science 5th Class Chapter 2 Microorganisms Solved Exercise

General Science

5th Class

Chapter 2

Microorganisms

Questions

1. Encircle the correct option.

i. Mushrooms belong to which group?

a. Viruses        b. Fungi        c. Bacteria        d. Protozoa

ii. What causes polio?

a. Protozoa        b. Virus        c. Fungi        d. Bacteria

iii. Penicillium is an example of which group?

a. Protozoa        b. Fungi        c. Bacteria        d. Viruses

iv. Food is contaminated due to the presence of _________ in the environment.

a. Moisture        b. Microorganisms        c. Air        d. Heat

v. Which one of the following is not a microorganism?

a. Bacteria        b. Virus        c. Algae        d. Ant

2. Write short answers.

i. What is a pathogen? How does it enter in the bodies of organisms?

Ans.

The microorganisms that cause diseases in their hosts are called pathogens. They enter in the body of organisms by the following way.

• Through air
• Through water
• Through food
• Through animals

ii. Why are some bacteria and fungi called decomposers?

Ans.

Some bacteria and fungi can change dead bodies into simple components only certain species of fungi and bacteria take part in decomposition. They used it as food.

iii. Write two benefits and two harmful effects of bacteria.

Ans.

Benefits of bacteria:

Bacteria help in the digestion and absorption of food in our small intestine. Bacteria help in preparation of food items.

Harmful effects of bacteria:

Bacteria cause diseases in organisms. Bacteria are responsible for spoiling of fruits and vegetables.

iv. How does the microorganism yeast work to soften and rise dough of flour?

Ans.

In baking industry, when flour is dough for the formation of different bakery product. A small amount of yeast is added it in the presence of micro-organisms. These microorganisms in yeast break down starch in the flour which produces carbon dioxide gas during fermentation that  makes the dough rise and soften.

v. How does a mosquito transmit disease?+

Ans.

When a mosquito bites and sucks blood of a patient. It takes pathogen from a patient. Then it bites a healthy person and transmits those pathogens (present in its saliva) to him. In this way, a mosquito spreads disease.

3. Constructed Response Questions:

i. The soil of forests of hot climate is always hot and moist, whereas the soil of forests of cold climate is cold and dry. Out of these two areas where the decomposition of fallen leave will happen more quickly? Explain.

Ans. The soil of forest which is hot and moist will helpful in decomposition of fallen leaves more quickly.

4. Investigate:

i. "All microorganisms are harmful and cause diseases". Prove that this idea is incorrect:

Ans. No all microorganisms are not harmful and not cause of diseases. Many microorganisms are used in welfare for the mankind.

ii. Many people use antibacterial soap to kill the bacteria present on their hands. But due to excessive use of soap, the chance of getting infection increases instead of decreasing. Why does it happen?

Ans. The excessive use of soap on hands skin become more dry it may also cause inflammation of skin and other skin problem.

5. Project:

The effect of quantity of sugar on the release of carbon dioxide from yeast:

Material Required:

i. Teaspoon

ii. Rubber band

iii. Balloons

iv. Transparent bottle of one litre (4 number)

v. Marker

vi. Yeast

vii. Sugar

viii. Warm water

Ans: Practical Work

Procedure:

i. Take four transparent plastic bottles and label them as I,II,III and IV. Add a spoon of yeast in each bottle.

Bottle	Amount of Sugar (Tea spoons)	Bottle	Amount of Sugar (Tea spoons)
i	0	ii	1
iii	2	iv	3

ii. Add sugar in each bottle as per given table. Do not add sugar in the first bottle.

iii. Pour half cup of the hot water in each bottle. Immediately, put a balloon at the mouth of each bottle and bind it strongly with rubber band.

iv. Shake each bottle strongly so that its contents can mix up.

v. Leave all the bottles in this condition for twenty minutes.

vi. Then observe:

a. Which balloon gets inflated the most?

Ans: Number (iv) balloon gets inflated.

b. In which bottle, most carbon dioxide gas was produced?

Ans: In (iv) bottle most carbon dioxide gas was produced.

General Science 5th Class Chapter 10 Technology in Everyday Life Solved Exercise

General Science

5th Class

Chapter 10

Technology in Everyday Life

Questions

1. Encircle the correct option.

i. We check the horizontal surface level by using a:

a. plumb line        b. metre rule        c. spirit level        d. triangle

ii. What does a mason use to keep a wall vertical?

a. Metre rule        b. Spirit level        c. Triangle        d. Plumb line

iii. Saline water is used for:

a. cleaning wounds        b. drinking by patients

c. washing hands        d. taking a bath

iv. Sterilized gauze is used:

a. for checking blood pressure        b. as bandage on wound

c. for finding the body temperature        d. for cleaning workplace

v. The emergency phone call number is:

a. 2211        b. 1133        c. 1122        d. 0911

2. Write short answers.

i. What do you need to make a model of a footbridge?

Ans.

To make a model of foot bridge we need skewer, thread, glue. wood, planes, nail and paper.

ii. What is the difference between the functions of spirit level and plumb line?

Ans.

Spirit Level:

Spirit level is used by carpenter, masons frame makers. Spirit level is used to check whether a surface is horizontal.

Plumb Line:

Plumb line is used to check the straight level of flag pole. Masons used it to construct and check the erect direction of wall.

iii. What is an LED?

Ans.

LEDs are the tiny light emitting bulbs. When a small voltage of 2 to 3 volts is applied across and LED, it starts glowing. Lights of different colours are emitted by different LEDs.

iv. You have to install a picture frame on the wall. How can it be kept straight horizontally as well as vertically?

Ans.

When we want to install a picture frame on the wall. We should used spirit level and plumb line, it will keep it straight horizontally as well as vertically.

v. What is meant by first aid?

Ans.

First aid is a temporary care given to a person who has got sudden illness or injury.

General Science 5th Class Chapter 9 Space and Satellites Solved Exercise

General Science

5th Class

Chapter 9

Space and Satellites

Questions

1. Encircle the correct option.

i. Countless shining lights seen at night on the sky are:

a. stars        b. moons        c. planets        d. different heavenly bodies

ii. How long does it take for a geo-stationary satellite to complete one orbit?

a. one day        b. one week        c. one month        d. one year

iii. First man to step on the Moon?

a. Edwin Aldrin        b. Neil Armstrong        c. Yuri Gagarin        d. Alan Shepard

iv. The system locates the position of an object on the Earth's surface is:

a. GRS        b. GMS        c. GPS        d. PGS

v. The first artificial satellite was sent into space in:

a. 1945        b. 1957        c. 1969        d. 1973

2. Write short answers.

i. Write five benefits which we get from artificial satellites.

Ans.

Radio television transmission and information by internet reached in each part of the world because of artificial satellite. We can make contact at far off places by telephone. We can correctly locate our position any where in the world. We can known about changes in the weather much earlier. This helps us to deal with floods, storms, forest fires and other disasters effectively.

ii. Moon is the natural satellite of the Earth. Is the Earth also a satellite of some bigger object? What is that object?

Ans.

Moon is natural satellite of the Earth. Earth is a natural satellite of the sun.

iii. Why does a geo-stationary satellite appear to be stationary?

Ans.

The geo-stationary satellites revolving in the orbits around the Earth with the same speed as that of the Earth therefore they are appeared to be stationary at any place.

iv. Why do the astronauts wear space dress? What are its benefits?

Ans.

Astronauts wear space dress for travelling in space without space dress and precaution measures astronauts can not survive in space. Space dress also protects astronauts from pressure and radiations.

v. Why can a telescope installed on a satellite take clearer photographs than from the Earth surface?

Ans.

A telescope is installed on a satellite to take the clear photographs and videos. These are more clear and informative than photographs taken from Earth because there is no air, water, dust and soil particles.

General Science 5th Class Chapter 8 Structure of the Earth Solved Exercise

General Science

5th Class

Chapter 8

Structure of the Earth

Questions

1. Encircle the correct option.

i. The outer layer of the Earth is called:

a. external core        b. mantle        c. crust        d. inner core

ii. What are the main types of the soil?

a. silt, sand and rock        b. clay, humus and sand

c. sand, silt and clay        d. silt, humus and clay

iii. Which type of soil is good for growth of plants?

a. sand        b. silt        c. clay        d. rock

iv. What is the role of living organisms in the soil?

a. making soil soft and airy        b. making soil hard

c. making soil unfit for cultivation        d. making the air dry

v. The amount of fresh water on the Earth is:

a. about 1%        b. about 30%        c. about 70%        d. about 97%

vi. What is important in the natural manure?

a. minerals        b. the decayed matter        c. sand        d. salts

2. Write short answers.

i. What is the outer layer of the Earth called? What is its importance in our life?

Ans.

The outer layer of the earth is called crust. It is that part on the earth where we live. This part contains mountains, deep oceans, rivers, deserts, green fields, rural and urban dwellings.

ii. Which soil is useful to make pottery? What are its properties?

Ans.

Clay is used to make pottery.

Properties: The wet clay can be moulded into any shape. It retains its shape when dried and becomes more harder.

iii. Which matter is obtained from decayed plants and insects?

Ans.

Humus, a decayed matter is obtained due to decomposition of plants and insects.

iv. What part of the Earth's surface consists of oceans? Why can we not drink sea water?

Ans.

The 71% of the earth surface is covered by water. About 97% is the salted water in the oceans, we can not drink sea water due to dissolved salts.

v. Where is the water found in the form of solid, liquid and gas (vapours)?

Ans.

Water is found on earth in three states of matter. In solid form, it is found in mountain and glaciers. In liquid state, it is found in rivers and lakes, while in vapour phase it exists as clouds.

General Science 5th Class Chapter 7 Electricity and Magnetism Solved Exercise

General Science

5th Class

Chapter 7

Electricity and Magnetism

Questions

1. Encircle the correct option.

i. The flow of current in an electric circuit is controlled by:

a. bulb        b. copper wire        c. switch        d. rubber

ii. Current can easily pass through:

a. steel paper clip        b. glass strip        c. plastic comb        d. wooden spoon

iii. How many poles are there on a ring shaped magnet?

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

iv. A freely suspended bar magnet always stays along:

a. east-west direction        b. north-south direction

c. any direction        d. keeps oscillating

v. Which one is a true statement?

a. North pole attracts north pole        b. North pole repels north pole

c. South pole repels north pole        d. South pole attracts south pole

2. Write short answers.

i. Why does a bulb light up in a closed circuit?

Ans.

When we switch on, the circuit is completed and the current starts flowing which lights up the bulb.

ii. You are given a bulb. What other components are required to light it up?

Ans.

We required an electric wire of copper, a battery and a switch.

iii. Why does an iron nail stuck to a magnet attract another nail?

Ans.

When an iron nail stuck to a magnet, it has magnetic properties, due to this reason an iron nail attracts another nail.

iv. How are directions known using a magnet compass?

Ans.

Place the magnet compass on earth. It suspended North-South direction. Now rotate the compass even that it comes in of North-South directions. By this, we can find out direction of any place.

v. A balloon is charged by rubbing it with a woolen cloth. Why does it stick to a wall when brought near it?

Ans.

When we rub a balloon with woolen cloth it becomes charged, so it sticks to the wall.

General Science 5th Class Chapter 6 Light and Sound Solved Exercise

General Science

5th Class

Chapter 6

Light and Sound

Questions

1. Encircle the correct option.

i. How does light travel in air?

a. In a circle        b. Along curved path

c. Along a straight line        d. In dispersed path

ii. Which object reflects maximum light?

a. White paper        b. Coloured paper        c. Mirror        d. Brick wall

iii. Speed of sound is maximum in:

a. a metal wire        b. air        c. water        d. vacuum

iv. Which of the following sounds is called noise?

a. Sound of a flute        b. Rustling of leaves

c. Pressure horn        d. Chirping of birds

v. When water comes in the way of sound travelling through air:

a. sound will stop        b. sound will slow down

c. sound will become fast        d. no effect on the speed of sound

2. Write short answers.

i. What is a transparent object? Write the name of three transparent objects.

Ans.

The objects through which light can pass completely are called transparent objects. We can see clearly across them. For example, mirror, glasses and glass filled with water are transparent thing.

ii. When is your shadow the shortest and longest in the sunlight.

Ans.

In morning and evening the shadows are longest, while in noon our shadow is shortest in the sunlight.

iii. The Moon is non-luminous like our Earth. How does it looks luminous to us?

Ans.

The moon is non-luminous object like our Earth but it looks luminous due to sunlight, it absorbs sunlight and reflects to make itself bright.

iv. Can you be a winner while running with your shadow? Give the reason also.

Ans.

No we cannot win with our shadow because shadow forms beyond the object (body).

v. When a train is moving away from you, will the intensity of its sound increase or decrease?

Ans.

When a train is moving away from you, intensity of sound will decrease.

3. Constructed Response Questions:

i. "Ears are raised" is a phrase in Urdu. The ears of some animals such as hare and rat are actually raised up? When and why?

Ans. The hare and rat rise up their ears due to presence of predator around their surrounding.

ii. Wood and charcoal are naturally non-luminous objects. Can they be made luminous? How?

Ans. Yes wood and charcoal can be luminous by ignition of match stick.

iii. How can you compare the speed of light and speed of sound coming from the lightning?

Ans. The speed of light is greater than speed of sound. This is the reason that we see the light first then its sound during lightning.

iv. Mark () for pleasant sounds and mark () for unpleasant sounds in the given pictures.

Ans. 

4. Investigate:

i. How you seen the ears of a frog, locust and fish? How do these animals hear sounds?

Ans. Frog, locust and fish do not have ears, but they can hear the sound by ear like internal structure and skin.

ii. By using torch, find out how much light passes from the objects given below?

Ans. 

5. Project:

i. Make a pinhole camera by using cardboard box, wax paper or tissue paper. Observe the image formed by it. On which principle of light does it works? What are the characteristics of images?

Ans.

ii. Make a simple musical instrument using a wooden board, iron nails, thin steel wires of different lengths and a hammer. On which principle foes this instrument work? Observe also the intensity of sound produced by it.

Ans.

General Science 5th Class Chapter 5 Physical and Chemical Changes of Matter Solved Exercise

General Science

5th Class

Chapter 5

Physical and Chemical Changes of Matter

Questions

1. Encircle the correct option.

i. The change of milk into yogurt is:

a. Physical change        b. Climate change

c. Chemical change        d. Change of colour

ii. Why did a person paint his iron gate?

a. To save from rusting        b. To save from sunlight

c. To make it beautiful        d. To save from water

Out of these which answer is correct?

a. 1 and 2        b. 1 and 3        c. 2 and 3        d. 1 and 4

iii. Which factor will not affect the dissolving of sugar in water?

a. Adding salt in water        b. Making sugar powder by grinding

c. Heating water and sugar        d. Stirring water and sugar

iv. Which one is not a chemical change?

a. Seed germination        b. Making paper boat

c. Burning of wood        d. Cooking food

v. What type of change is it when metal expands on heating?

a. Permanent        b. Chemical        c. Physical        d. Temporary

2. Write short answers.

i. Explain evaporation giving examples from everyday life.

Ans.

The change of water into water vapours is called evaporation. From wet surfaces, water continuously moves in to the surrounding air, this process occurs continuously from the surfaces of canals, lakes, rivers and oceans etc. This process also takes place from the snow surface and from the leaves of plants.

ii. Define condensation.

Ans.

The change of water vapours in to liquid and stick with the external surface of glass is called condensation.

iii. What is rusting and which type of change is this?

Ans.

The change that occurred on the iron due to the action of oxygen and water is called rusting. This is a permanent chemical change.

Iron + Oxygen + Water = Rusting

iv. Give an example of chemical change in which carbon dioxide is produced?

Ans.

When slaked lime is added in water it produces carbon dioxide.

v. Explain the three states of matter and their interconversion.

Ans.

Solid is the state in which matter maintains a fixed volume and shape. Liquid takes the shape of its container. Gas spreads out to fill any container. All the three states of matter are changed in one another on heating for example ice (solid) changes into liquid (water), and liquid (water) changes into gas (steam).

3. Constructed Response Questions:

i. Weigh one fourth of a glass of vinegar and tea spoon of baking soda. Then mix them together. As a result, bubbles will be formed. Weigh this compound again. Now its weigh will become less than the previous one. How will you explain the loss of the weigh?

Ans. There is a chemical reaction occur due to which gas is released in the form of bubbles due to this, there is loss of weight.

ii. On mixing vinegar and boiling water bubbles are produced. Out of the two one is chemical change and the other one is physical change. Explain.

Ans. On mixing vinegar there is chemical change, due to which bubbles of gas evolved, while boiling of water is a physical change.

iii. A student weighs a piece of ice and then allows it to melt. In your opinion what will be the weight of water and why?

Ans. The weight of water will decrease because some water evaporates from the surface.

4. Investigate:

i. Why is the formation of fertilizer from leaves is a chemical change?

Ans. The formation of fertilizer from leaves is a chemical process because once leaves is rotten to form it, they will never become reversed into their original condition.

5. Project:

Removal of Eggs Shell by Chemical Process.

Material Required:

• Egg
• Vinegar
• Vessel to keep eggs

i. Table an egg in a vessel or jar. Pour vinegar on it so that the egg is immersed into it. Bubbles will be formed on the egg's surface.

ii. Leave it for 12 hours. Carefully take out the egg from the vessel then was it gently and observe the egg.

iii. You will observe that the shell of the egg has disappeared.

iv. What have you come to know from this observation?

Ans: When egg is immersed in a jar on pouring the vinegar, the egg shell is dissolved due to chemical change.

General Science 5th Class Chapter 4 Environmental Pollution Solved Exercise

General Science

5th Class

Chapter 4

Environmental Pollution

Questions

1. Encircle the correct option.

i. Which disease is caused due to air pollution?

a. Diarrhea        b. Typhoid        c. lung cancer        d. Cholera

ii. The germs present in it cause typhoid.

a. Sewerage water        b. Fertilizers        c. Factory waste        d. Insecticides

iii. Which one of these is non-biodegradable?

a. Feathers        b. Paper        c. Leaves of plants        d. Polythene bag

iv. Which of the following is NOT a greenhouse gas?

a. Oxygen        b. Methane        c. Ozone        d. Carbon dioxide

v. Which one of the following acts causes most of the air pollution?

a. Collecting rubber        b. Burning rubber

c. Reusing rubber        d. Recycling rubber

2. Write short answers.

i. Write three causes of air pollution.

Ans.

1.  Smoke emitted from vehicles and factories pollute air.

2. The burning of fuels in the kilns and homes produces carbon dioxide gas which pollutes the air.

3. The fire in the forests also causes air pollution.

ii. What are the four effects of pollution on life?

Ans.

1. Germs present in pollutes water are cause of the diseases.

2. Bacteria present in sewerage use most of the dissolved oxygen present in water. The aquatic animals e.g. fish die due to lack of oxygen.

3. Pollutant gases present in smog cause lungs diseases and allergy.

4. Poisonous substances and gases are produced by open garbage dumps. These substances cause air and water pollution.

iii. What is greenhouse effect?

Ans. Green house effect is a natural process. That warms the earth surface when sun energy reaches the earth atmosphere some of it reflected back and the rest is absorbed. Due to this earth atmosphere is getting hot.

iv. What will be the effects of global warming?

Ans.

The climate of the world is changing due to global warming. Therefore, the sea level is rising due to melting of ice on poles of earth. It is causing more rains and floods. If this process continues, the coastal and islands may disappear in the sea.

v. Write three ways of preventive measures to reduce pollution.

Ans.

1. We should use public transport instead of personal vehicles.

2. Cutting of trees and forests should be reduced.

3. There should be more tree plantation.

3. Constructed Response Questions:

i. What is the main cause of pollution?

Ans. Following are the main causes of pollution:

• Garbage
• Wastes of factories
• Agriculture waste
• Smoke from vehicles
• Over population

ii. Why Government of Pakistan has banned the use of polythene bags?

Ans. Government of Pakistan has banned the use of polythene bag because they are non biodegradable substances and can not dissolve in environment. That is main cause of pollution.

iii. If it is written D2W on the polythene bags then why there is no ban on the use of such bags?

Ans. The polythene bag that is written with D2W are banned because they can dissolve after sometime in environment.

4. Investigate:

i. What is the relationship between diseases and pollution?

Ans. The main reason of disease spreading is pollution. Where there is more pollution, there will be more diseases.

ii. Identify biodegradable and non-biodegradable materials present in your environment. 

Ans. 

Biodegradable Materials	Non-Biodegradable Materials
Wood, Paper, Cloth, Peels fruits and vegetables	Glass pieces, polythene bag leather

5. Project:

Preparing Organic fertilizer

Material Required:

1. Plastic bucket
2. Peels of vegetables, fruits and egg shells
3. Grass
4. Dry leaves
5. Water
6. Wooden rod

Procedure:

1. In a small plastic bucket put peels of vegetables, fruits, egg shells, dry leaves and some grass
2. Pour water so that all of these become wet.
3. Stir with the help of a wooden rod that these can get oxygen.
4. When these things become brown it means the fertilizer has been made. It is called organic fertilizer. Now you can use it for plants.

General Science 5th Class Chapter 3 Flowers and Seeds Solved Exercise

General Science

5th Class

Chapter 3

Flowers and Seeds

Questions

1. Encircle the correct option.

i. The given figure is of a dicot seed. Which statement is correct about it?

a. Endosperm is present which stores food

b. There is no role of cotyledon in storing food

c. Cotyledon stores food for embryo

d. Cotyledon appears in the form of protective cap

ii. In the given picture of a flower, which are the reproductive parts of the flower?

              

a. A, B and D        b. B, C and D

c. A, B and C        d. A, C and D

iii. The gram seed is covered by which structure?

a. Cotyledon        b. Seed coat        c. Plumule        d. Endosperm

iv. Which conditions are necessary for seed germination?

a. Water, soil and air, darkness        b. Air, water, light

c. Water, temperature, air        d. Temperature, soil, light

v. Which type of pollination is must for papaya?

a. Self-pollination        b. Cross pollination

c. Both type of pollination        d. None of these

2. Write short answers.

i. Can you tell the names and functions of the four parts of a flower?

Ans.

1.  Sepals: hey protect the internal structures.

2. Petals: They attract insects and birds towards the flower.

3. Stamen: It is the male reproductive part.

4. Carpel: It is the female reproductive part.

ii. How will you compare self pollination and cross pollination?

Ans.

Self-Pollination:

If pollen grains are transferred from the anther of a flower to the stigma of the same flower or to the stigma of the other flower of the same plant, it is called pollination. It takes place in pea, cotton and tomato, etc.

Cross-Pollination:

If pollen grains are transferred from the flower of one plant to the stigma of the flower of another plant of the same type, it is called cross pollination. It takes place in maize, papaya and rose, etc.

iii. Compare gram and maize seed.

Ans. 

Gram Seed:

1. It has two cotyledons.

2. Endosperm is absent.

3. Embryo is present at the center of the seed.

Maize Seed:

1. It has one cotyledon.

2. Endosperm is present.

3. Embryo is present at one side of the seed.

iv. Define reproduction.

Ans.

Reproduction is the process by which organisms produce new organisms of their own kind for the continuation of their generation.

v. Label the given picture:

Ans.

3. Constructed Response Questions:

i. Observe the given picture and tell what is the role of water in seed germination?

Ans. Water help in seed germination providing suitable environment and also provide softness to seed cover.

ii. Observe the given pictures. For which type of pollination, the shapes and structures of flowers are suitable?

Ans. In diagram the shape of a and b flowers and structure is suitable for cross pollination while c and d is suitable for self pollination.

4. Investigate:

If all the insects become extinct, what will be its effect on flowering plants?

Ans. If all the insects become extinct, there is no pollination occurred in flowering plants so the generation of plants will not increase in large variety.

5. Project:

i. Collect five different types of flowers. See in which flowers sepals, petals, stamen, and carpels are present and in which these are not present. Compare these structures in different flowers.

ii. Using low-cost or no-cost materials, make a model of flower. Picture four models are given, for your guidance.

Ans: Practical Work

General Science 8th Class Chapter 12 Our Universe Solved Exercise

General Science

8th Class

Chapter 12

Our Universe

Questions

1. Encircle the correct option.

(i) An instrument that helps in seeing heavenly objects:

a. microscope        b. telescope        c. periscope        d. kaleidoscope

(ii) Telescope on the Earth suffers from the defect that light coming from the stars has to pass through:

a. space        b. water        c. atmosphere        d. clouds

(iii) A vehicle designed to carry an artificial satellite in outer space is:

a. rocket        b. airbus        c. jet plane    d. spacecraft

(iv) Star's distances are measured in:

a. kilometers        b. nautical miles        c. light years        d. miles

(v) The colour of hottest star is:

a. red        b. blue        c. yellow        d. white

(vi) Our solar system is a part of:

a. andromeda galaxy        b. milky way galaxy

c. jelly fish galaxy        d. irregular shaped galaxy

(vii) Surface temperature of the Sun is:

a. 3000  ̊ C       b. 6000  ̊ C        c. 15000  ̊ C        d. 1,500,000  ̊ C

(viii) The last stage in the life of massive star is:

a. red giant        b. white dwarf        c. super giant        d. black hole

(ix) Bright stars may appear dim stars because they are:

a. old star        b. new star        c. far away from Earth        d. close to the Earth

(x) The nearest star after the Sun is:

a. Rigel        b. Proxima Centauri        c. Aldebaran        d. Sirius

General Science 8th Class Chapter 11 Technology in Everyday Life Solved Exercise

General Science

8th Class

Chapter 11

Technology in Everyday Life

Questions

1. Encircle the correct option.

(i) Bio-plastic is made of:

a. glucose        b. proteins        c. starch        d. fats

(ii) Baking soda, calcium carbonate, glycerin, fluorides, etc. are usually used for making:

a. soaps        b. detergents        c. toothpaste        d. banaspati ghee

(iii) Soap is ________ salt of long chain fatty acids:

a. sodium or potassium        b. magnesium        c. Iodine        d. halogen

(iv) _________ is used in solar cooker

a. convex mirror        b. concave mirror        c. convex lens        d. concave lens

(v) Which is used in UPS?

a. Inverter        b. Electric generator        c. Compressor        d. Electric motor

General Science 8th Class Chapter 10 Electricity and Magnetism Solved Exercise

General Science

8th Class

Chapter 10

Electricity and Magnetism

Questions

1. Encircle the correct option.

(i) An electric circuit is the path along which

a. electrons revolve around the nucleus of an atom

b. electric charge flows

c. magnetic lines of force move

d. electric motors move

(ii) A closed circuit is the

a. complete path of electric current

b. incomplete path of electric current

c. broken path of electric current

d. none of the above

(iii) Which of the following is non-magnetic substance?

a. Iron        b. Steel        c. Silver        d. Nickel

(iv) Which of the following is a magnetic substance?

a. Glass        b. Marble        c. Gold        d. Cobalt

(v) The best material to be used as a core in the coils for making electromagnet is:

a. rubber        b. plastic        c. steel        d. soft iron

General Science 8th Class Chapter 9 Reflection and Refraction of Light Solved Exercise

General Science

8th Class

Chapter 9

Reflection and Refraction of Light

Questions

1. Encircle the correct option.

(i) Through which of the following the light travels the fastest?

a. Air        b. Vacuum        c. Water        d. Prism

(ii) What is the colour of an object that absorbs all the light that hits it?

a. Black        b. Green        c. White        d. Red

(iii) Which of the following type of mirror can from an image larger than the object?

a. Concave        b. Convex        c. Plane        d. All of these

(iv) Which of the following is true for an image in a plane mirror?

a. It is formed when light is blocked by an opaque object

b. It is formed when light passes through a transparent object

c. It is of the same shape, size and colour as the object

d. It is always black

(v) What happens when light hits a shiny or smooth surface?

a. It is disappeared        b. It is refracted

c. It is absorbed        d. It is reflected

(vi) How is the angle of incidence related to the angle of reflection?

a. It is greater        b. It is smaller

c. It is same        d. none of these

(vii) Which of the following describes the image of the boy formed by the plane mirror?

a. It will be upside down

b. It will be in front of the mirror

c. It will be larger than the boy

d. It will be horizontally reversed left to right