Class 8 Science

CBSE Class 8 Science Chapter 12 Some Natural Phenomena Long Answer Questions

Question 1. In the year 2013. There was a showcase at IIT Hyderabad. All the students from different schools and colleges were invited to that occasion. Navecn, with his friend wanted to so the projects made by M. Touch students. Ho found a project based on the construction of anti-earthquake buildings, in which the small houses of iron rods were constructed. One Muse was with a hose containing water, and the other was without a hose. They were shocked by the shaking of both houses.

1. Describe an earthquake.
Answer: A sudden shaking of the earth, which lasts for a very short time, is called an earthquake.

2. Explain the meaning of a quake-resistant building.
Answer: Quake-resist building means that the buildings should be constructed in such a way that it can withstand for more time even on shaking of the earth.

3. Mention which force reduces the shaking in a building with a hose.
Answer: The viscous force of water resists the oscillation or vibration of building caused by shaking of the earth and ultimately reduces the shaking in building with hose.

4. State your feelings about the students who showed their projects.
Answer: They used applications of science and technology and were more curious about the methods.

Question 2. Amit was travelling in a taxi when he saw lightning at some distance. He heard thunder after a few seconds.

1. What should Amit do immediately to remain safe?

1. Increase the speed of the car
2. Stop the car and remain seated inside
3. Stop the car and take shelter inside a building
4. Turn the car and travel in the opposite direction

Answer: 2. Stop the car and remain seated inside

2. Which of these conditions results in lightning?

1. Negative and positive charges meeting
2. The number of negative charges is increasing
3. The number of positive charges is increasing
4. Negative and positive charges are moving away from each other.

Answer: 1. Negative and positive charges meeting

3. A lightning conductor protects a building from lightning. What is a lightning conductor made of?

1. Glass
2. Metaal
3. Wood
4. Plastic

Answer: 2. Metaal

Question 3. The diagram shows the focus of an earthquake. Focus is the point inside the Earth’s crust where the earthquake originates. 1, 2, 3, and 4 are four locations on the Earth’s surface.

1. In which location will the effect of the earthquake be maximum?

1. Location 1
2. Location 2
3. Location 3
4. Location 4

Answer: 2. Location 2

2. Raju was in his garden when an earthquake hit the place. What should Raju do to remain safe?

1. Move to an open space
2. Run away from the place
3. Take shelter under a staircase
4. Take shelter under a large tree

Answer: 1. Move to an open space

Question 4. The Richter scale measures the strength of earthquakes

1. The damages from an earthquake are listed below.

1. 2 people died
2. 5 building roofs collapsed
3. 12 building walls collapsed

What could be the likely reading on the Richter scale for the earthquake?

1. 4.8
2. 5.4
3. 6.5
4. 7.3

Answer: 3. 6.5

Question 5. Which of these statements is true about the earthquake?

1. Earthquakes can cause soil erosion.
2. Most of the earthquakes occur in mountain regions.
3. The location and duration of earthquakes can be predicted.
4. Earthquakes are caused by the movement of underground plates.

Answer: 4. Earthquakes are caused by the movement of underground plates.

Question 6. Ryan ran two combs through his hair. He hung one comb from a stand using a thread. Ryan brought the other comb close to the first comb. The picture below shows the result.

1. Why did the comb move away from the other?
Answer: The comb moved away from the other because both the combs acquired the same or like charges when they were run through hair, and like charges repel each other.

2. Ryan repeats the activity using a pair of glass rods in place of the combs. What is most likely to happen in this case?

1. The hanging rod will move away
2. The hanging rod will come closer
3. The hanging rod will show no change
4. The hanging rod will start spinning.

Answer: 1. The hanging rod will move away

Question 7. Describe with the help of a diagram, an instrument that can be used to detect a charged body.
Answer: The instrument that is used to detect a charged body is an electroscope.

Construction

1. Take an empty jam bottle.
2. Take a piece of cardboard slightly bigger in size than the mouth of the bottle.
3. Pierce a hole in it so that a metal paper clip can be inserted.
4. Open out the paper clip.
5. Cut two strips of aluminium foil about 4 X 1 cm each. Hang them on the paper clip.
6. Insert the paper clip into the cardboard so that it is Perpendicular to it.
7. Charge a refill and touch it with the end of the paper clip.

Working

The aluminium foil strips receive the same charge from the charged refill through the paper clip. The strips carrying the same charge repel each other, and they become wide open.

Touch the end of the paper clip gently with your hand, and we will find a change in the foil strip. Repetition gives the same result.

CBSE Class 8 Science Chapter 3 Coal And Petroleum MCQs With Answers Multiple Choice Questions And Answers

Question 1. Various materials that are obtained from nature are called natural resources. Which of the following is not a natural resource?

1. Minerals
2. Water
3. Soil
4. Plastic

Answer: 4. Plastic

Question 2. The source of energy for the Earth’s water cycle is

1. Seas
2. Sun
3. Earth’s rotation
4. Minerals

Answer: 2. Sun

Question 3. Air is a natural resource and cannot be exhausted by human activities. It is known as an inexhaustible natural resource. Which of the following is another Inexhaustible natural resource?

1. Coal
2. Petroleum
3. Sunlight
4. Minerals

Answer: 3. Sunlight

Question 4. Which of the following is a pair of non-renewable natural resources?

1. Coal and soil
2. Air and sunlight
3. Water and petroleum
4. Trees and minerals

Answer: 3. Water and petroleum

Question 5. Exhaustible natural resources are

1. Made by human efforts
2. Not dependent on nature
3. Limited in quantity
4. Not exhausted by human activities

Answer: 3. Limited in quantity

Question 6. Which of the following is an exhaustible natural resource?

1. Soil
2. Air
3. Sunlight
4. Coal

Answer: 4. Coal

Question 7. Fossil fuels are obtained from

1. Remains of non-living materials
2. Dead remains of birds only
3. Dead remains of insects only
4. Dead remains of living organisms

Answer: 4. Dead remains of living organisms

Question 8. Coal is formed from the remains of

1. Vegetation only
2. Animals only
3. Both vegetation and animals
4. Neither vegetation nor animals

Answer: 3. Both vegetation and animals

Question 9. Which substance is formed by the carbonisation of dead vegetation?

1. Coal
2. Coke
3. Coal gas
4. Coal tar

Answer: 1. Coal

Question 10. When coal burns in the air

1. Nitrogen is formed
2. Sulphur dioxide is formed
3. Oxygen is formed
4. Carbon dioxide is formed

Answer: 4. Carbon dioxide is formed

Question 11. Coal is processed in Industries to got some useful products. Which of the following Is not obtnlnod from coal?

1. Coke
2. Coal tar
3. Coal gas
4. CNG

Answer: 4. CNG

Question 12. Which by-product is obtained after processing coal?

1. Diesel
2. Petrol
3. Coke
4. Paraffin wax

Answer: 3. Coke

Class 8 Science Chapter 12 Some Natural Phenomena Activity 1

Aim: To prove that an object gets electrically charged by rubbing.

Material Required: A ball pen refill, a small piece of paper, dry leaf, polythene, etc.

Procedure 

1. Firstly, take a ball pen refill and rub it vigorously with a piece of polythene.
2. Now, bring it close to a piece of paper. Be ensure that the rubbed part of the refill should not be touched by our hand. We will find that the refill attracts the tiny pieces of paper.
3. Repeat the activity with small pieces of dry leaf, husk, and mustard seeds and note down the observation. We will find that the refill attracts the tiny pieces in each case.

Conclusion: We can conclude that when the plastic refill is rubbed with polythene, dry leaf, or mustard seeds, etc., it acquires a small electric charge.

Class 8 Science Chapter 12 Some Natural Phenomena Activity 2

Aim: To record that different objects get electrically charged when rubbed with different materials.

Material Required: Refill, balloon, eraser, steel spoon, polythene, dry hair, silk cloth.

Procedure:

1. Collect the objects given in the table and rub them against the materials listed next to them in the table.
2. Bring the charged object (rubbed object) close to tiny pieces of paper and observe, it attracts or not.
3. Record your observations in the table.

Conclusion: We have concluded from the observation table that the objects rubbed with different materials get charged and attract tiny pieces of paper, except the steel spoon, because it is a good conductor.

Class 8 Science Chapter 12 Some Natural Phenomena Activity 3

Aim: To understand the interaction between two types of electric charges.

Material Required: Two inflated balloons, two refills, woollen cloth, polythene.

Procedure:

• Firstly, hang two inflated balloons in such a way that they do not touch each other.
• Now, rub both the balloons with a woollen cloth and release them.
• We will observe that both balloons start repelling each other. They both acquire the same negative charge.

• Now, bring a plastic refill and rub it with polythene. It with acquire some charge.
• Place this charged plastic refill in a glass tumbler using the tumbler as a stand.
• Now, take another plastic refill and rub it with polythene and bring it close to the charged refill, which is already placed in a glass tumbler.

We will find that. The charged refill in the tumbler moves away. It means both the refills repel each other, as they acquire the same charges, that is positive charge.

• Again, rub a refill with polythene and place it gently in a glass tumbler as before.
• Now, bring an inflated charged balloon near the refill.

We will observe that the charged refill moves towards the charged balloon. As they both acquire different charges.

Conclusion: We have concluded from the activity that like charges repel each other and unlike charges attract each other.

Class 8 Science Chapter 12 Some Natural Phenomena Activity 4

Aim: To understand the working ofan electroscope. Material Required: An empty jam bottle, a cardboard, a metal paper clip, two small pieces of aluminum foil, and a refill.

Procedure:

1. Choose an empty jam bottle and take a piece of cardboard slightly bigger in size than the mouth of the bottle.
2. Now, pierce a hole in the cardboard so that a metal paper clip can be inserted.
3. Cut two strips of aluminum foil about 4cm x 1 cm each. Hang them on the paper clip as shown in the figure.
4. Now, fix the paper clip in the cardboard lid, so that it gets perpendicular to it as shown in the figure.
5. Now, charge a refill and touch it with the end of the paper clip. We can see that the two aluminium foils move away from each other.
6. Gently, touch the other charged bodies with the ends of a paper clip. Here, we find no differences in the working of foil strips.

Conclusion: We have concluded that a charged body transfers all its charges to aluminium foil through a paper clip

Which causes the aluminium leaves to diverge. Therefore, the greater the amount of electric charge on a body, the greater the aluminium leaves will diverge.

Class 8 Science Chapter 12 Some Natural Phenomena Activity 5

Aim: To prepare a short report on the suffering of the people during and after the earthquakes.

Material Required: Newspapers, magazines.

Procedure:

1. Collect some newspapers and magazines from different publishers.
2. Read the articles carefully based on the earthquakes.
3. Now, collect some pictures showing the damage caused by these earthquakes from these newspapers and magazines.
4. Make a short report on the destruction caused by earthquakes.

Conclusion: An Earthquake is a natural calamity. It is a sudden shaking or trembling of the earth which lasts for a short time. Some of the damaging effects ofan earthquake are as follows

1. The earthquake may cause landslides and tsunamis in hilly and coastal areas.
2. An earthquake may break a groundwater pipe, which disrupts the water supply system.
3. An earthquake brings destruction to buildings, dams, railway tracks, roads, etc.
4. The earthquake may cut off the communication system, and the affected areas may get disconnected from the rest of the world.

Class 8 Science Chapter 12 Some Natural Phenomena Activity 6

Aim: To make a report of some devastation caused by the tsunami in India.

Material Required: A political world map.

Procedure:

1. Firstly, take a world map.
2. Now, locate the eastern coast and the Andaman and Nicobar islands in India. Mark other countries around the Indian Ocean that could have suffered damage from the tsunami.
3. Now, collect some information from your parents or other elders to make a report of the devastation caused by the tsunami in India.
4. Prepare a report in neat and clean handwriting.

Conclusion: We have located the eastern coast of India, the Andaman and Nicobar Islands, and other countries around the Indian Ocean.

Some information about the devastation caused by the tsunami in India is given above.

A major tsunami occurred in the Indian Ocean on 26th December 2004. At 8:38 AM, an earthquake of 6.1 magnitudes was felt in Andaman Island. At 9:00 AM, this affected India’s South-Eastern coast.

Thousands of people died, and many people lost their families. The coastal area was destroyed. Many fisherman and their community were ruined by the tsunami. It was one of the most devastating natural calamities, people have ever witnessed.

Class 8 Science Chapter 12 Some Natural Phenomena Fill In The Blanks

Question 1. When charges move, they constitute an electric current.
Answer: Electric

Question 2. __________types of charges are gained by rubbing objects.
Answer: Two

Read And Learn More CBSE Class 8 Science Question And Answers

Question 3. The process of transfer of charge from a charged object to the Earth is called
Answer: Earthing

Question 4. A lightning strike could destroy__________ and
Answer: Life, Property

Question 5. Lightning conductor can_____________ buildings from the effect of lightning.
Answer: Protect

Question 6. An earthquake is caused by a _______ deep inside the Earth’s crust.
Answer: Disturbance

Question 5. Static charges can be induced by ________.
Answer: Rubbing

Question 6. ________ is a device used to protect buildings from the effects of lightning.
Answer: Lightning conductor

Question 7. An earthquake is caused due to the movement of plates in the Earth’s crust.
Answer: Tectonic

Class 8 Science Chapter 12 Some Natural Phenomena True Or False

Question 1. The process of electric discharge cannot occur between clouds and the Earth.
Answer: False

Question 2. Bathing outdoors should be avoided during a thunderstorm.
Answer: True

Question 3. Earthquakes can occur anytime, all over the world.
Answer: True

Question 4. The plates of the outermost layer of the Earth are always in continuous motion.
Answer: True

Question 5. Tremors on the Earth can be caused by the eruption of a volcano
Answer: True

Class 8 Science Chapter 12 Some Natural Phenomena Match The Columns

Answer: A-7,B-4,C-1,D-2,E-3,F-4,G-5

Class 8 Science Chapter 12 Some Natural Phenomena Assertion-Reason Questions

The following questions consist of two statements -Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false
4. A is false, but R is true.

Question 1.

Assertion (A): Maximum damage occurs at the epicentre.
Reason (R): The Destructive energy of an earthquake is measured on the Richter scale.

Answer: 2. Both A and R are true, but R is not the correct explanation of A.

Question 2.

Assertion (A): We should not use an umbrella while crossing an open field during a thunderstorm.
Reason (R): As the rod of the umbrella and its supporting wires are made up of metals, it may affect the person who holds the umbrella

Answer: 1. Both A and R are true, and R is the correct explanation of A.

The following questions consist of two statements: Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

Question 1.

Assertion (A) The most destructive earthquakes have a magnitude of more than 7 on the Richter scale.
Reason (R) We should move inside our houses or tall buildings during earthquakes.

Answer: We should not move inside our house or tall buildings during an earthquake because tall buildings may collapse and cause an accident.

Question 2.

Assertion (A) A charged body repels an uncharged body.
Reason (R) Like charges repel each other while unlike charges attract each other.

Answer: A charged body always attracts an uncharged body

Question 3.

Assertion (A): An earthquake is a sudden shaking or trembling of the earth which lasts for a short time.
Reason (R): The plates inside the Earth’s crust collide with one another, which causes earthquakes.

Answer: Earthquakes are caused by sudden shaking and the collision of plates inside Earth’s crust.

Question 4.

Assertion (A): An electroscope is a device that is used to test whether an object is carrying a charge or not.
Reason (R): The Electroscope is based on the transfer of charges.

Answer: An Electroscope determines whether any object is charged or not by the transfer of charges.

CBSE Class 8 Science Chapter 3 Coal And Petroleum Long Answer Questions

Question 1. Ravi prefers to go to school by pooling car. On other occasions he likes to opt for public transport rather than private transport. For short distances, he walks or uses a bicycle.

1. Which means of transport do you think is best for short distances?

1. Small vehicles
2. Bicycles
3. Large vehicles
4. Motor bike

Answer: 2. Bicycle, as it is an eco-friendly and cost-effective mode of transport, which can be used for short distances.

2. Which department advises people to save petrol/diesel while driving?

1. UNESCO
2. Traffic department
3. PCRA
4. NHAI

Answer: 3. PCRA (Petroleum Conservation Research Association) advises people to save petrol/diesel while driving.

List The Major Products Obtained From Petroleum And Their Uses, Class 8

Question 2. The picture shows how petroleum and natural gas are extracted through oil wells

Which of the following statements is supported by the picture?

Circle ‘Yes’ or ‘No’ for the correct response.

Answer:

1. Yes
2. No, gases are lighter than liquids (petroleum)
3. Yes

2. Which of these conditions is required for the formation of natural gas?

1. Low pressure
2. Presence of air
3. High temperature
4. Presence of water

Answer: 3. High temperature

3. Which of these petroleum products is used for heavy motor vehicles?

1. LPG
2. Diesel
3. Petrol
4. Kerosene

Answer: 2. Diesel

4. What is the advantage of using CNG instead of petrol in light motor vehicles?

1. It can be stored easily
2. It can be extracted easily
3. It causes less air pollution
4. It releases more energy on combustion

Answer: 3. It causes less air pollution.

Question 3. The table shows two groups of natural resources.

1. Which of these statements is true about coal? Circle ‘Yes’ or ‘No’ for the correct response.

Answer:

1. No
2. Yes, coal is formed from plant remains buried deep under the Earth.
3. Yes, the formation of coal requires high temperature and high pressure.

2. Where is a coal reserve most likely to be found?

1. Inside volcanoes
2. Beneath glaciers
3. On the ocean floors
4. Under the land surface

Answer: 4. Under land surfaces

3. Which gas is mainly emitted during the combustion of coal?
Answer: Carbon dioxide

4. Coke is a product obtained by the processing of coal. Which of these is a byproduct of making coke?

1. Coal tar
2. Bitumen
3. Coal gas
4. Kerosene

Answer: 3. Coal gas

5. The material X is a fossil fuel. It is formed from the buried large land plants (vegetation) by a very slow process. When X is heated in the absence of air, it gives three products, A, B, and C.
Answer: A is used in steel making, B is used as an industrial fuel, whereas product C has been traditionally used for metallising the roads. It is now replaced by a petroleum product, bitumen.

CBSE Class 8 Science Chapter 11 Chemical Effects Of Electric Current Multiple Choice Questions

Question 1. Plastic wire is

1. An insulator
2. A conductor
3. Both 1 and 2
4. None of these

Answer: 1. An insulator

Question 2. Electrolytes conduct electricity due to the movement of

1. Electrodes
2. Atoms
3. Electrons
4. Ions

Answer: 4. Ions

Question 3. The solution that can conduct electricity is of

1. Pure water
2. Water and acid solution
3. Water and salt solution
4. Both B and C

Answer: 3. Water and salt solution

Question 4. Which one of the following solutions will not conduct electricity?

1. Lemon rice
2. Vinegar
3. Tap water
4. Vegetable oil

Answer: 4. Vegetable oil

Question 5. Boojho and Paheli performed experiments taking similar bulbs and cells but two different solutions A and B as shown in figure.

They found that the bulb in setup A glows more brightly as compared to that of setup B. You would conclude that

1. Higher Current Is Flowing Through The Circuit In Set Up A
2. Higher Current Is Flowing Through The Circuit In Set B
3. Equal Current Is Flowing Through Both The Circuits
4. The Current Flowing Through The Circuits In The Two Setups Cannot Be Compared In This Manner

Answer: 1. Higher Current Is Flowing Through The Circuit In The Setup A

Question 6. Observe the following circuits. In which circuit will the bulb glow? Write ‘Yes’ or ‘ No’ in the blank space provided along with each of the circuits given in the figure.

Answer:

1. No
2. Yes
3. No
4. Yes

Question 7. Observe the figure.

Which of these two circuits, A or B, shows the correct observation? It is not clear from the diagram what A and B.

So cannot predict the actual solution. But if we compare with the activity. This seems to be a potato, and the correct diagram is A because the positive terminal makes the green spot on the potato.

Question 8. 

Which of the following solutions will not make the bulb glow in the figure?

1. Sodium chloride
2. Copper sulphate
3. Silver nitrate
4. Sugar solution in diluted water

Answer: 4. Sugar solution in diluted water

Question 9. The process of depositing a thin layer of any superior metal over an object made of a cheaper metal with the help of electricity is called

1. Electro refining
2. Electro-metallurgy
3. Electroplating
4. None Of the Above

Answer: 3. Electroplating

Question 10. Which of the following metals is used in electroplating to make objects appear shiny?

1. Iron
2. Copper
3. Chromium
4. Aluminium

Answer: 3. Chromium

Question 11. Boojho’s uncle has set up an electroplating factory near his village. He should dispose of the waste of factory waste

1. In the nearby river
2. In the nearby pond
3. In the nearby corn field
4. According to the disposal guidelines of the local authority

Answer: 4. According to the disposal guidelines of the local authority.

Short Answer Type Questions

Question 12. Boojho made the circuit as shown in the figure. He wanted to observe what happens when an electric current is passed through water, but he forgot to add a few drops of lemon juice to the water. Will it make any difference to his observations? Explain

Answer: Adding few drops of lemon juice in water will increase the conductivity of the solution. The current will flow in both the cases but adding of lemon juice makes it easy for the current to flow.

Question 13. Observe the following circuit given in the figure.

Current does not flow in the circuit if there is a gap between the two wires. Does It Indicate that air is a poor conductor of electricity? Does air never conduct electricity? Explain.?
Answer: Yes, current is not flowing through the air gap between the wires, It means that air Is a poor conductor of electricity.

Air conducts electricity only when there is a great voltage or when there is some moisture in the air.

Question 14. Boojho made the circuit given in Figure and observed that the bulb did not glow. On Paholl’s suggestion, he added one more cell in the circuit. The bulb now glows. Explain.

Answer: Initially, the bulb was not glowing because the voltage required to make the bulb glow was not sufficient. When the voltage increases more than a particular value, the bulb starts glowing because it gets sufficient energy to heat its filament.

Question 15. Paheli setup an experiment using liquid A in the beaker as shown in figure. She observed that the bulb glows. Then, she replaced the liquid A by another liquid B. This time the bulb did not glow. Boojho suggested replacing the bulb by an LED. They observed that the LED glows. Explain.

A is a good conductor of electricity, and it allows the maximum current to pass through it, which is sufficient to glow the bulb.

But when it is replaced by another liquid B, the bulb does not glow because liquid B is not a good conductor of electricity. But the small current which is passing through B is sufficient to glow a low-voltage LED, so it glows.

CBSE Class 8 Science Chapter 3 Coal And Petroleum Short Answer Questions

Question 1. Some natural resources are given below. Classify them into the exhaustible and inexhaustible natural resources.
Air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen
Answer: Exhaustible natural resources are coal, natural gas, petroleum, minerals, and forests. Inexhaustible natural resources are air, sunlight, and oxygen.

Question 2. Sunlight and air are inexhaustible natural resources. Comment.
Answer: These resources are present in an unlimited quantity in nature and are not likely to be exhausted by human activities.

Read And Learn More CBSE Class 8 Science Short Answer Questions

Question 3. You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?
Answer: Decantation can be used to separate a mixture of petroleum and water. The mixture is allowed tostand. Carefully, lighter layer can be poured and separated without disturbing the heavier one.

Question 4. Write the name of the products obtained when coal is heated strongly in the absence of air.
Answer: When coal is heated strongly in the absence of air in closed retorts, various useful products are obtained. These are coke, coal tar, and coal gas.

Question 5. Why should we use petrol or diesel only when necessary?
Answer: We should use these fuels only when necessary because

1. It will reduce air pollution and thus lead to a better environment.
2. It will reduce the risk of global warming.
3. It will ensure their availability for a longer period.

Question 6. Where do we get coal from and how Is It formed?
Answer: About 300 million years ago, the Earth had dense forests in low-lying wetland areas. Due to natural processes like flooding, these forests got buried under the soil and deposited as fossils. Due to high temperature and pressure, dead plants slowly converted into coal.

Question 7. Write the difference between coke and coal.
Answer: The Differences between coke and coal are as follows

Question 8. Write the characteristics and some important uses of coal.
Answer: Characteristics of coal are as follows:

1. Coal is a hard, black combustible fuel.
2. It is a fossil fuel.
3. It mainly contains carbon.
4. When heated in air, coal burns and produces mainly carbon dioxide gas.
5. It is a source of energy

CBSE Class 8 Science Chapter 3 Coal And Petroleum Very Short Answer Questions

Question 1. Give two natural resources. Why are these called natural resources?
Answer: Air and water are natural resources because they are obtained from nature.

Question 2. We will use all our natural resources forever. Is it possible?
Answer: No, we cannot use all our natural resources forever. Some natural resources are going to be exhausted.

Read And Learn More CBSE Class 8 Science Very Short Questions And Answers

Question 3. Can air, water, and soil be exhausted by human activities?
Answer: No, these will not be exhausted by human activities.

Question 4. Coal, petroleum, and natural gas are called fossil fuels. Why?
Answer: Coal, petroleum, and natural gas are called fossil fuels because they are formed by the decomposition of the remains of prehistoric plants and animals (fossils) buried under the Earth long ago.

Question 5. What do you mean by carbonisation?
Answer: The slow process of conversion of dead vegetation into coal is called carbonisation.

Question 6. Name two fuels obtained from petroleum that can be used as domestic fuels.
Answer: Petrol, liquefied petroleum gas (LPG), as obtained from petroleum and can be used as a domestic fuel.

Question 7. Where is coal found in India?
Answer: In India, coal is found mainly in Jharkhand, West Bengal, Odisha, and Madhya Pradesh.

Question 8. How can you define Coke?
Answer: Coke is a tough, porous, and black substance and an almost pure form of carbon.

CBSE Class 8 Science Chapter 11 Short Answer Questions

Question 1. Boojho made the circuit as shown in the figure. He wanted to observe what happens when an electric current is passed through water, but he forgot to add a few drops of lemon juice to the water. Will it make any difference to his observations? Explain

Answer: Adding few drops of lemon juice in water will increase the conductivity of the solution. The current will flow in both the cases but adding of lemon juice makes it easy for the current to flow.

Question 2. Observe the following circuit given in the figure.

No current does not flows in the circuit if there is a gap between the two wires. Does It Indicate that air is a poor conductor of electricity? Does air never conduct electricity? Explain.
Answer: Yes, current is not flowing through the air gap between the wires, which means that air is a poor conductor of electricity.

Air conducts electricity only when there is a great voltage or when there is some moisture in the air.

Read And Learn More CBSE Class 8 Science Short Answer Questions

Question 3. Boojho made the circuit given and observed that the bulb did not glow. On Paholl’s suggestion, I added one more cell in the circuit. The bulb now glows. Explain.

Answer: Initially, the bulb was not glowing because the voltage required to make the bulb glow was not sufficient. When the voltage increases more than a particular value, the bulb starts glowing because it gets sufficient energy to heat its filament.

Question 4. Paheli setup an experiment using liquid A in the beaker as shown in figure. She observed that the bulb glows. Then, she replaced the liquid A by another liquid B. This time the bulb did not glow. Boojho suggested replacing the bulb by an LED. They observed that the LED glows. Explain.

Answer: Liquid A is a good conductor of electricity, and it allows the maximum current to pass through it, which is sufficient to glow the bulb.

But when it is replaced by another liquid B, the bulb does not glow because liquid B is not a good conductor of electricity. But the small current that is passing through B is sufficient to glow a low-voltage LED, so it glows.

Question 5. Last Monday, Ankush woke up late in the morning. So, he saw the time and suddenly realised that he had been late for an interview, which he was supposed to give after reaching the venue by the right time. Immediately, he turned ON the geyser, but it did not work. He got more tense, then he used an electric iron rod through which he could get some boiled water for his bath.

There was an earthing problem in the switchboard, which he was unaware of. He was barefoot and was just about to switch ON the electric iron rod, but at the same time, he was stopped from doing so by one of his roommates living with him. It could be dangerous for Ankush. Explain briefly what could have happened with Ankush. If he switched ON the electric iron rod (without wearing any slippers on his feet). Mention the values shown by Ankush’s friend.

Answer: If Ankush switched ON the electric iron rod and (without wearing any footwear), then he could have met with some accident, either in the form of electrical sparking or a short circuit of the switchboard.

Ankush’s friend seems to be very intelligent and very much concerned for Ankush as well.

Question 6. Observe the following circuits. In which circuit will the bulb glow? Write ‘Yes’ or ‘ No’ in the blank space provided along with each of the circuits given in the figure.

Answer:

1. No
2. Yes
3. No
4. Yes

Question 7. Name of three liquids which, when tested in the manner shown in the figure below, may cause the magnetic needle to deflect.

Answer: The three liquids are as follows

1. Tapwater
2. HC1 or hydrochloric acid
3. Sodium hydroxide

Question 8. The bulb does not glow in the setup shown in the figure below. List the possible reasons. Explain your answer

Answer: The possible reasons are as follows

1. The current is not produced by the given liquid, and hence, the bulb does not glow.
2. Connections are loose.
3. The bulb is fused.
4. Cells are used up.

Question 9. A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A, while it glows very dimly for liquid B. You would conclude that

1. Liquid A is a better liquid than Liquid II
2. Liquid in a heller liquid A
3. Both liquids are equally conducting
4. Conducting properties of liquid annuli are compared in this manner

Answer: We conclude that liquid A is a better conductor than liquid II

Question 10. Does pure water conduct electricity? If not, what can we do to make it conducive?
Answer: No, pure water does not conduct electricity because it has no dissolved salt in it.

Hence, pure water can be made conducting by dissolving salt in it.

Class 8 Science Chapter 3 Coal And Petroleum Fill In The Blanks

Question 1. Forests and coal are ________ natural resources
Answer: Exhaustible

Question 2. Coal is one of the _______ used to cook food.
Answer: Fuels

Question 3. Sunlight is a _____ natural resource.
Answer: Inexhaustible

Read And Learn More CBSE Class 8 Science Question And Answers

Question 4. Petroleum ____ and _____ are fossil fuels.
Answer: Coal, natural gas

Question 5. The slow process of conversion of dead vegetation into coal is called _____.
Answer: Carbonisation

Question 1. Fossil fuels are________,______ and _______.
Answer: coal, petroleum, natural gas

Question 2. The process of separation of different constituents from petroleum is called _______.
Answer: Refining

Question 3. The least polluting fuel for a vehicle is ______.
Answer: Compressed Natural Gas (CNG)

Question 6. In India, ______ advises people to save petrol and diesel while driving their vehicles
Answer: PCRA (Petroleum Conservation Research Association)

Question 7. The main constituent of natural gas is ______.
Answer: Methane

Class 8 Science Chapter 3 Coal And Petroleum True Or False

Question 1. Fossil fuels can be made in the laboratory.
Answer: False, Fossil fuels are made by a natural process.

Question 2. CNG is a more polluting fuel than petrol.
Answer: False, CNG is a clean fuel and less polluting than petrol.

Question 3. Coke is almost a pure form of carbon.
Answer: True

Question 4. Coal tar is a mixture of various substances.
Answer: True

Question 5. Kerosene is not a fossil fuel.
Answer: False, Kerosene is a kind of fossil fuel

Question 6. Resources that are present in unlimited quantities in nature are called nonrenewable natural resources.
Answer: False, Resources that are present in unlimited quantity in nature are called inexhaustible natural resources.

Question 7. Oxygen in the air is an exhaustible natural resource.
Answer: False, Oxygen in the air is an inexhaustible natural resource because it is continuously recycled in the atmosphere.

Question 8. Wildlife is an exhaustible natural resource.
Answer: True

Question 9. CNG is a less polluting fuel than petrol and diesel.
Answer: True

Question 10. Under high temperature and pressure, dead plants slowly converted to coal.
Answer: True

Question 11. Bitumen is used for lubrication in vehicles.
Answer: False

Question 12. Coal tar has been used for metalling the roads.
Answer: True

Class 8 Science Chapter 3 Coal And Petroleum Match The Columns

Question 1. Match Column 1 with Column 2

Answer: A-3, B-4, C-1, D-2

Question 2. Match Column 1 with Column 2

Answer: A-4, B-2, C-1, D-3

Question 10. Match Column 1 with Column 2.

Answer: The correct match is A-2, B-1, C-3, D-4

The following questions consist of two statements: Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true.

Question 1.

• Assertion (A) Sunlight is an inexhaustible natural resource.
• Reason (R) The Sun will continue to radiate energy.

Answer: (1) Both A and R are true, and R is the correct explanation of A.

Question 2.

1. Assertion (A) Kerosene is used in jet aircraft.
2. Reason (R) Kerosene is not a fossil fuel.

Answer: 3. A is true, but R is false

Question 3.

1. Assertion (A) Coke is a pure form of carbon.
2. Reason (R) It is used in the manufacture of steel.

Answer: 2. Both A and R are true, but R is not the correct explanation of A

Question 4.

1. Assertion (A) CNG stands for compressed natural gas.
2. Reason (R) CNG is stored under high pressure.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 5.

1. Assertion (A): Exhaustible resources are limited in nature.
2. Reason (R) Fossil fuels are an example of exhaustible resources.

Answer: (1) Both A and R are true, and R is the correct explanation of A.

Class 8 Science Chapter 3 Coal And Petroleum

The following questions consist of two statements, Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

Question 11.

1. Assertion (A) We get different constituents such as petrol, kerosene, diesel, etc. from petroleum.
2. Reason (R) The process of separating the various useful constituents (fractions) of petroleum is known as refining.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 12.

1. Assertion (A): Coal should not be burned in a closed room.
2. Reason (R): Coal releases carbon dioxide.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 13.

1. Assertion (A) Natural gas is a very important fossil fuel.
2. Reason (R) It produces oxygen while burning.

Answer: 3. A is true, but R is false.