Frank Cce Everyday Science Solutions for Class 8 Science Chapter 15 Some Natural Phenomena are provided here with simple step-by-step explanations. These solutions for Some Natural Phenomena are extremely popular among Class 8 students for Science Some Natural Phenomena Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Frank Cce Everyday Science Book of Class 8 Science Chapter 15 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Frank Cce Everyday Science Solutions. All Frank Cce Everyday Science Solutions for class Class 8 Science are prepared by experts and are 100% accurate.

Page No 231:

Question A:

Answer:



Page No 232:

Question B.1:

Answer:

(b) conductor

An electric charge can flow only through a conductor.

Page No 232:

Question B.2:

(b) conductor

An electric charge can flow only through a conductor.

Answer:

(a) will attract each other

When two objects are rubbed against each other, opposite charges develop on the objects because of the transfer of electrons from one object to the other, and they attract each other.

Page No 232:

Question B.3:

(a) will attract each other

When two objects are rubbed against each other, opposite charges develop on the objects because of the transfer of electrons from one object to the other, and they attract each other.

Answer:

(c)  detect, measure and find the nature of charge

A gold leaf electroscope is used to detect, measure and find the nature of a charge.

Page No 232:

Question B.4:

(c)  detect, measure and find the nature of charge

A gold leaf electroscope is used to detect, measure and find the nature of a charge.

Answer:

(a) Lightning

Lightning is the name given to the electric discharge between the clouds, or clouds, and the ground.

Page No 232:

Question B.5:

(a) Lightning

Lightning is the name given to the electric discharge between the clouds, or clouds, and the ground.

Answer:

(a) focus

The focus of an earthquake is the point of origin of the earthquake inside the earth.

Page No 232:

Question B.6:

(a) focus

The focus of an earthquake is the point of origin of the earthquake inside the earth.

Answer:

(a) Fault zone

A seismic zone is also called a fault zone.

Page No 232:

Question B.7:

(a) Fault zone

A seismic zone is also called a fault zone.

Answer:

(a) Seismology

Seismology is the study of earthquakes.

Page No 232:

Question B.8:

(a) Seismology

Seismology is the study of earthquakes.

Answer:

(a) electroscope

An electroscope is used to test an electric charge.

Page No 232:

Question B.9:

(a) electroscope

An electroscope is used to test an electric charge.

Answer:

(b) negative charge

When an atom gains an electron, it becomes negatively charged.

Page No 232:

Question B.10:

(b) negative charge

When an atom gains an electron, it becomes negatively charged.

Answer:

(a) positive charge

When an atom loses an electron, it becomes positively charged.

Page No 232:

Question C:

(a) positive charge

When an atom loses an electron, it becomes positively charged.

Answer:

1. Electric current flows through a conductor.
2. Electric charge is due to the loss or gain of electrons.
3. Unlike charges attract each other.
4. Human body is a good conductor of electricity.
5. Current electricity was discovered by Benjamin Franklin.
6. A fracture in the earth's crust is called fault .
7. The molten rocks are called lava.
8. The magnitude of an earth quake defines the energy released.
9. The upper solid layer of the earth is called crust.



Page No 233:

Question 1:

1. Electric current flows through a conductor.
2. Electric charge is due to the loss or gain of electrons.
3. Unlike charges attract each other.
4. Human body is a good conductor of electricity.
5. Current electricity was discovered by Benjamin Franklin.
6. A fracture in the earth's crust is called fault .
7. The molten rocks are called lava.
8. The magnitude of an earth quake defines the energy released.
9. The upper solid layer of the earth is called crust.

Answer:

A snake cannot hear the sound. They only follow the movement of the snake charmer and his flute (been). They consider the flute a predator and respond to its movements.

Page No 233:

Question 2:

A snake cannot hear the sound. They only follow the movement of the snake charmer and his flute (been). They consider the flute a predator and respond to its movements.

Answer:

Woollen or synthetic clothes are made of wool or synthetic fibre. Both of them are non-conductors of electricity; hence, they can easily build an electric charge. When they are moved, an electric discharge takes place, which we hear as a sound. As this discharge takes place close to the ear while we take off the clothes, we hear a crackling sound.

Page No 233:

Question 3:

Woollen or synthetic clothes are made of wool or synthetic fibre. Both of them are non-conductors of electricity; hence, they can easily build an electric charge. When they are moved, an electric discharge takes place, which we hear as a sound. As this discharge takes place close to the ear while we take off the clothes, we hear a crackling sound.

Answer:

Lightning is a very heavy flow of charge between clouds or between clouds and the earth.
In hilly areas, clouds are comparatively closer to the ground than in the plains. Therefore, lightning strikes are more frequent in hilly areas.

Page No 233:

Question 4:

Lightning is a very heavy flow of charge between clouds or between clouds and the earth.
In hilly areas, clouds are comparatively closer to the ground than in the plains. Therefore, lightning strikes are more frequent in hilly areas.

Answer:

It might be dangerous to raise an umbrella over our head in a thunderstorm because the metal ferrule of the umbrella is a good conductor of electricity. So, during a thunderstorm, the possibility of an electric shock from lightning is higher if we use an umbrella with a metal ferrule than if we use an umbrella with a wood or plastic ferrule.

Page No 233:

Question D:

It might be dangerous to raise an umbrella over our head in a thunderstorm because the metal ferrule of the umbrella is a good conductor of electricity. So, during a thunderstorm, the possibility of an electric shock from lightning is higher if we use an umbrella with a metal ferrule than if we use an umbrella with a wood or plastic ferrule.

Answer:

  Column A   Column B
1. Good conductor of electricity (c) Moist air
2. Always repel each other (a) Like charges
3. Bad conductor of electricity (d) Dry air
4. Electrons are (e) Negatively charged
5. Always attract each other (b) Unlike charges
 

Page No 233:

Question E:

  Column A   Column B
1. Good conductor of electricity (c) Moist air
2. Always repel each other (a) Like charges
3. Bad conductor of electricity (d) Dry air
4. Electrons are (e) Negatively charged
5. Always attract each other (b) Unlike charges
 

Answer:

1. False

Like charges repel and unlike charges attract each other.

2. True

3. True

4. False

When an electron is removed from a body, the body acquires a positive charge.

5. True

6. False

The origin of an earthquake inside the earth is called its focus.

7. False

The Gujarat (Bhuj) earthquake occurred in 2001.

8. False

Landslides occur more frequently during the rainy season.

9. True

Page No 233:

Question A.1:

1. False

Like charges repel and unlike charges attract each other.

2. True

3. True

4. False

When an electron is removed from a body, the body acquires a positive charge.

5. True

6. False

The origin of an earthquake inside the earth is called its focus.

7. False

The Gujarat (Bhuj) earthquake occurred in 2001.

8. False

Landslides occur more frequently during the rainy season.

9. True

Answer:

Silk cloth acquires a negative charge when it is rubbed against a glass rod.

Page No 233:

Question A.2:

Silk cloth acquires a negative charge when it is rubbed against a glass rod.

Answer:

Our body is a conductor of electricity.

Page No 233:

Question A.3:

Our body is a conductor of electricity.

Answer:

No, an electric charge cannot flow through an ebonite rod as it is an insulator; however, an electric charge can reside on its surface.

Page No 233:

Question A.4:

No, an electric charge cannot flow through an ebonite rod as it is an insulator; however, an electric charge can reside on its surface.

Answer:

A gold leaf electroscope is used to detect and measure a charge and find the nature of the charge.

Page No 233:

Question A.5:

A gold leaf electroscope is used to detect and measure a charge and find the nature of the charge.

Answer:

A tremor is an effect produced by the travelling seismic waves, and it shakes the earth.

Page No 233:

Question A.6:

A tremor is an effect produced by the travelling seismic waves, and it shakes the earth.

Answer:

The Richter scale is used to measure the magnitude of earthquakes.

Page No 233:

Question A.7:

The Richter scale is used to measure the magnitude of earthquakes.

Answer:

Tsunami waves hit the Indian Ocean on 26 December 2004.

Page No 233:

Question A.8:

Tsunami waves hit the Indian Ocean on 26 December 2004.

Answer:

Volcanic eruptions of Mt. Vesuvius destroyed the cities of Pompeii and Herculaneum.

Page No 233:

Question B.1:

Volcanic eruptions of Mt. Vesuvius destroyed the cities of Pompeii and Herculaneum.

Answer:

A seismograph is a sensitive instrument that can detect, amplify, and record earthquakes as well as other ground vibrations that are too small to be perceived by human beings.



Page No 234:

Question B.2:

A seismograph is a sensitive instrument that can detect, amplify, and record earthquakes as well as other ground vibrations that are too small to be perceived by human beings.

Answer:

A volcanic eruption is caused because of the pressure created by molten rocks (lava) inside the crust of the earth.

Page No 234:

Question B.3:

A volcanic eruption is caused because of the pressure created by molten rocks (lava) inside the crust of the earth.

Answer:

Soil liquefaction is the process of transformation of soil into liquid because of the shaking of the earth, which causes saturated soil to lose its strength and behave like a liquid.

Page No 234:

Question B.4:

Soil liquefaction is the process of transformation of soil into liquid because of the shaking of the earth, which causes saturated soil to lose its strength and behave like a liquid.

Answer:

The phenomenon by which an equal and opposite charge is induced in an uncharged body when a charged body is held close to it is called charging by induction. During this phenomenon, the two bodies are not in contact with each other.

Page No 234:

Question B.5:

The phenomenon by which an equal and opposite charge is induced in an uncharged body when a charged body is held close to it is called charging by induction. During this phenomenon, the two bodies are not in contact with each other.

Answer:

Charging by conduction is a process in which a charged body is brought in contact with an uncharged body, and the uncharged body gets a charge similar to that of the charged body.

Page No 234:

Question B.6:

Charging by conduction is a process in which a charged body is brought in contact with an uncharged body, and the uncharged body gets a charge similar to that of the charged body.

Answer:

The following are two uses of the electroscope.
1. To detect a charge in a body
2. To determine the nature of the charge

Page No 234:

Question B.7:

The following are two uses of the electroscope.
1. To detect a charge in a body
2. To determine the nature of the charge

Answer:

An earthquake is a vibration or tremor in the earth's crust, caused by disturbances originating deep inside the crust.

Page No 234:

Question B.8:

An earthquake is a vibration or tremor in the earth's crust, caused by disturbances originating deep inside the crust.

Answer:

The focus of an earthquake is the point in the earth’s crust from where the shock waves of the earthquake originated.
The epicentre of an earthquake is the point on the surface of the earth directly above the focus.

Page No 234:

Question B.9:

The focus of an earthquake is the point in the earth’s crust from where the shock waves of the earthquake originated.
The epicentre of an earthquake is the point on the surface of the earth directly above the focus.

Answer:

An earthquake may have the following causes.
1. Disturbances originating deep inside the earth’s crust
2. A sudden volcanic eruption on the earth's surface

Page No 234:

Question B.10:

An earthquake may have the following causes.
1. Disturbances originating deep inside the earth’s crust
2. A sudden volcanic eruption on the earth's surface

Answer:

The following are the effects of earthquakes.
1. They can cause large-scale damage to houses, other buildings and roads.
2. They can cause floods, landslides and tsunamis.

Page No 234:

Question C.1:

The following are the effects of earthquakes.
1. They can cause large-scale damage to houses, other buildings and roads.
2. They can cause floods, landslides and tsunamis.

Answer:

Electric charge is a property of some elementary particles that gives rise to an interaction between them. 
A gold leaf electroscope can be used to detect an electric charge in a body.
When an electric charge is brought in contact with a gold leaf electroscope, either divergence or convergence of the leaves of the electroscope takes place, depending upon the nature of the electric charge. Thus, we can detect the charge on a body using a gold leaf electroscope.

Page No 234:

Question C.2:

Electric charge is a property of some elementary particles that gives rise to an interaction between them. 
A gold leaf electroscope can be used to detect an electric charge in a body.
When an electric charge is brought in contact with a gold leaf electroscope, either divergence or convergence of the leaves of the electroscope takes place, depending upon the nature of the electric charge. Thus, we can detect the charge on a body using a gold leaf electroscope.

Answer:

Lightning is a phenomenon observed because of atmospheric electricity. A bright streak of light accompanied by a thundering sound is observed when an electric charge jumps from one cloud to another or from a cloud to the earth's surface.
Lighting may be very dangerous as it may harm animals and human beings. It can cause fires and may destroy buildings.
A lighting conductor is based upon the principle that an electric charge flows through a path of least resistance.

Page No 234:

Question C.3:

Lightning is a phenomenon observed because of atmospheric electricity. A bright streak of light accompanied by a thundering sound is observed when an electric charge jumps from one cloud to another or from a cloud to the earth's surface.
Lighting may be very dangerous as it may harm animals and human beings. It can cause fires and may destroy buildings.
A lighting conductor is based upon the principle that an electric charge flows through a path of least resistance.

Answer:

During a thunderstorm, when there is lightning, one should take the following precautions.
1. One should stay in the house and should not touch electrical wires, telephone cords, etc.
2. When outside the house, one should try to stay in a vehicle, such as a car or a bus.
3. When outside the house and there is no shelter nearby, one should sit on the ground with the hands on the knees.

Moreover, tall buildings can be fitted with lightning conductors as a precaution.

Page No 234:

Question C.4:

During a thunderstorm, when there is lightning, one should take the following precautions.
1. One should stay in the house and should not touch electrical wires, telephone cords, etc.
2. When outside the house, one should try to stay in a vehicle, such as a car or a bus.
3. When outside the house and there is no shelter nearby, one should sit on the ground with the hands on the knees.

Moreover, tall buildings can be fitted with lightning conductors as a precaution.

Answer:

Rub an ebonite rod with wool and hang it with a thread. Rub another ebonite rod with wool and bring it near the suspended rod. We will find that the two ebonite rods repel each other.
This happens because an ebonite rod, on rubbing with wool, acquires a negative charge. When this ebonite rod is brought near another ebonite rod carrying a similar charge, they repel each other. This shows that like charges repel each other.

Now, take a glass rod and rub it with silk and bring it near the charged ebonite rod. We will observe that the glass rod attracts the ebonite rod. This happens because a glass rod, on rubbing with silk, acquires a positive charge. When this glass rod is brought near an ebonite rod carrying an opposite charge, they are attracted to each other. This shows that unlike charges attract each other.

Page No 234:

Question C.5:

Rub an ebonite rod with wool and hang it with a thread. Rub another ebonite rod with wool and bring it near the suspended rod. We will find that the two ebonite rods repel each other.
This happens because an ebonite rod, on rubbing with wool, acquires a negative charge. When this ebonite rod is brought near another ebonite rod carrying a similar charge, they repel each other. This shows that like charges repel each other.

Now, take a glass rod and rub it with silk and bring it near the charged ebonite rod. We will observe that the glass rod attracts the ebonite rod. This happens because a glass rod, on rubbing with silk, acquires a positive charge. When this glass rod is brought near an ebonite rod carrying an opposite charge, they are attracted to each other. This shows that unlike charges attract each other.

Answer:

When two clouds with unlike charges come very close to each other, there is a heavy flow of electric charge between the clouds. During this process, a large amount of energy is released in the form of heat, light and sound. This causes lightning and thunder during a storm.
When lightning strikes a tree or a high building, an opposite charge is developed in the tree or the building, which causes a heavy flow of electric charge between the cloud and the tree or the building. This flow of charge can cause a fire.

Page No 234:

Question C.6:

When two clouds with unlike charges come very close to each other, there is a heavy flow of electric charge between the clouds. During this process, a large amount of energy is released in the form of heat, light and sound. This causes lightning and thunder during a storm.
When lightning strikes a tree or a high building, an opposite charge is developed in the tree or the building, which causes a heavy flow of electric charge between the cloud and the tree or the building. This flow of charge can cause a fire.

Answer:

A rescue and relief team should take the following steps in areas affected by earthquakes.
1. Organise relief camps for people who have lost their houses
2. Carry the injured to hospital
3. Try to find people trapped inside buildings

Page No 234:

Question C.7:

A rescue and relief team should take the following steps in areas affected by earthquakes.
1. Organise relief camps for people who have lost their houses
2. Carry the injured to hospital
3. Try to find people trapped inside buildings

Answer:

The followings are measures that can be taken to minimise the damage caused by an earthquake.
1. Buildings should be designed in such a way that they remain as individual units when they are subjected to vibrations.
2. River banks should be made strong by using building materials.
3. In hilly areas, lighter materials should be used to make houses.
4. People should be made aware of precautionary measures that should be taken during an earthquake.

Page No 234:

Question C.8:

The followings are measures that can be taken to minimise the damage caused by an earthquake.
1. Buildings should be designed in such a way that they remain as individual units when they are subjected to vibrations.
2. River banks should be made strong by using building materials.
3. In hilly areas, lighter materials should be used to make houses.
4. People should be made aware of precautionary measures that should be taken during an earthquake.

Answer:

The following are the steps that should be taken for the construction of earthquake-resistant houses and for minimising the damage caused by earthquakes.
1. In highly seismic areas, timber should be used in place of bricks and concrete .
2. The roofs should be made as light as possible.
3. Quake-proof norms for construction should be implemented.
4. Fire-fighting equipment should be installed in buildings.

Page No 234:

Question C.9:

The following are the steps that should be taken for the construction of earthquake-resistant houses and for minimising the damage caused by earthquakes.
1. In highly seismic areas, timber should be used in place of bricks and concrete .
2. The roofs should be made as light as possible.
3. Quake-proof norms for construction should be implemented.
4. Fire-fighting equipment should be installed in buildings.

Answer:

If we find someone trapped inside a building under rubble, we would first remove the rubble, by using a simple implement if necessary. If this is not possible, then we would inform the police or a non-governmental organisation (NGO) for help to remove the rubble. We would then provide first aid to the person. If the person has suffered a serious injury, we would take him or her to a nearby hospital.

Page No 234:

Question C.10:

If we find someone trapped inside a building under rubble, we would first remove the rubble, by using a simple implement if necessary. If this is not possible, then we would inform the police or a non-governmental organisation (NGO) for help to remove the rubble. We would then provide first aid to the person. If the person has suffered a serious injury, we would take him or her to a nearby hospital.

Answer:

We should take the following steps when we are in school and there is an earthquake.
1. We should keep away from heavy objects.
2. We should take shelter under a desk.
3. If we are in an open ground outside the school building, then we should maintain a distance from the building and trees.
4. If we are inside the school, then we should maintain a distance from bookcases, mirrors, windows and other heavy objects.



View NCERT Solutions for all chapters of Class 8