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Class VIII science lesson, Essays (high school) of Computer science

Computer science

It will help you to learn some questions

Typology: Essays (high school)

2025/2026

Uploaded on 01/09/2026

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JAIN HAPPY SCHOOL
(A Minority Educational Institution)
CLASS-VIII
SCIENCE
Lesson 11 QA
A. Choose the most appropriate answer.
Ans: 1. a 2.d 3. b 4. c 5. b 6. c 7. d 8. b
B. VERY SHORT-ANSWER QUESTIONS: Give one-word
answers.
Ans: 1. True 2. repel 3. attract 4. negative charge 5. True 6.
negative 7. Ind
uction 8. conduction 9. electroscope 10. charged 11.
electricity, yes 12. Electric discharge 13. True 14. negative
15. same 16. Richter 17. seismogram, seismic 18. False 19.
True
C. SHORT-ANSWER QUESTIONS (TYPE I): Answer in a
sentence or two.
1. Why does a comb rubbed on hair attract pieces of paper?
Ans: The comb on rubbing became gets electrically charged
and attract pieces of paper.
2. Under what conditions do charges attract or repel each
other?
Ans: Like charges repel each other whereas opposite
charges attract each other.
3. Why do we say that only repulsion is a sure test of
charge on a body?
Ans: A charged body can attract an uncharged body and
body with an opposite charge. Thus, repulsion alone is a
sure test of whether a body is charged or not.
4. What do you mean by 'charging by conduction'? What
kind of charge does the body acquire?
Ans: When a neutral object is charged by touching it with a
charged body, it is called charging by conduction. The
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JAIN HAPPY SCHOOL

(A Minority Educational Institution)

CLASS-VIII

SCIENCE

Lesson 11 QA

A. Choose the most appropriate answer. Ans: 1. a 2.d 3. b 4. c 5. b 6. c 7. d 8. b B. VERY SHORT-ANSWER QUESTIONS: Give one-word answers. Ans: 1. True 2. repel 3. attract 4. negative charge 5. True 6. negative 7. Ind uction 8. conduction 9. electroscope 10. charged 11. electricity, yes 12. Electric discharge 13. True 14. negative

  1. same 16. Richter 17. seismogram, seismic 18. False 19. True C. SHORT-ANSWER QUESTIONS (TYPE I): Answer in a sentence or two.
  2. Why does a comb rubbed on hair attract pieces of paper? Ans: The comb on rubbing became gets electrically charged and attract pieces of paper.
  3. Under what conditions do charges attract or repel each other? Ans: Like charges repel each other whereas opposite charges attract each other.
    1. Why do we say that only repulsion is a sure test of charge on a body? Ans: A charged body can attract an uncharged body and body with an opposite charge. Thus, repulsion alone is a sure test of whether a body is charged or not.
    2. What do you mean by 'charging by conduction'? What kind of charge does the body acquire? Ans: When a neutral object is charged by touching it with a charged body, it is called charging by conduction. The

object acquires the same charge as that on the charged body.

  1. What is 'charging by induction'? What kind of charge does the body acquire? Ans: When a neutral object is charged by bringing a charged body near it without touching it, it is called charging by induction. The object acquires an opposite charge to that of the charged body.
  2. What is the difference between conductors and non- conductors? Give two examples of each. Ans: Substances which allow electric charges to flow through them are called conductors of electricity. Examples: Metals like iron, copper, aluminium, etc. Substances that do not allow electric charges to flow through them are called non-conductors or insulators of electricity. Examples: Plastic, rubber, wood, etc.
  3. What is an electroscope? Ans: An electroscope is a device used to detect and measure electric charge.
  4. What is 'earthing'? The process of transferring of charge from a charged object to the earth is known as earthing. A lightning conductor on a building transfers the charges from a cloud to safely flow through it to the earth. D. SHORT-ANSWER QUESTIONS (TYPE H): Answer in about 30 words.
  5. Explain why, when two bodies, charged by rubbing them together, acquire equal and opposite charge. Ans: Every atom has equal number of positive and negative electric charges. The positively charged particles are firmly bound in the atom while the negatively charged particles are more loosely bound. Thus, by rubbing it is possible to remove some of the negatively charged particles. This is why when two bodies are charged by rubbing them together one acquires positive charge by loosing positively charge

shut the windows. (iii) Do not take shelter under a tree (iv) stay away from trees and poles (v) If you are in an open place squat low on the ground.

  1. What is the Richter scale? Why do we say that it is not a linear scale? Ans: An instrument used to measure the magnitude or intensity of an earthquake is called Richter scale. The number indicating the magnitude or intensity on Richter scale ranges between 0 and 9. The Richter scale is not a linear scale because on this scale, the vibrations of an earthquake with a magnitude of 2 are 10 times greater in amplitude than those of an earthquake with a magnitude of
  3. List three effects of an earthquake. Ans: The effects of earthquakes include deformation of ground surface, damage and destruction of humanmade structures, towns and cities, loss of life, violent devastating fires, landslides, floods, etc. E.LONG ANSWER QUESTIONS: Answer in about 60 words.
  4. Draw a labelled diagram of a gold-leaf electroscope. Describe how you will use it to detect a charge, measure a charge, and find the nature of the charge. Ans: The gold-leaf electroscope consists of a metal disc to which a metal rod is attached. The metal rod passes into a bell jar through a tightly-fitted rubber stopper. At the bottom of the metal rod are mounted two thin strips (or leaves) of metal. These can be made of copper, brass or gold. The bell jar rests on a wooden base. Tin foil is attached to the sides of the bell jar. The gold-leaf electroscope is used to detect and measure charge. The amount of divergence of the leaves is a measure of the amount of charge on the body. To test whether a body has a positive or negative charge, at first we charge the electroscope with a known charge. If the divergence of the leaves increases, the body has a similar charge. If the

divergence of the leaves decreases the body has opposite charge, i.e. it is positively charged.

  1. Explain how lightning occurs between two clouds during a storm. Ans: When two clouds with unlike charges come near each other, there can be a very heavy discharge between them. Huge amount of energy is released in the form of heat, light and sound during such a discharge. This is the lightning we see and the thunder we hear during a storm.
  2. Explain the process of lightning striking a building or tree. Ans: Clouds can charge tall buildings and trees by induction. The buildings and trees thus acquire the opposite charge. If the build up of charge is very heavy, easily flow from cloud to tree or building. This can be very dangerous and can result in the building or the tree catching fire because of the huge amount of energy released.
  3. In what ways is lightning useful? Ans: Lightning is also useful in many ways: (i) The heat and light released during lightning combine nitrogen of the air to oxygen to form nitrogen oxides. When rain occurs nitrogen oxides dissolved in water and form dilute nitric acid, which comes down with rain. The Rhizobium bacteria present in root of plants convert it into nitrogenous compounds, which are essential for growth of plants. (ii) Lightning also enables ozone to be formed from oxygen. The ozone present in air stops the harmful ultraviolet rays of the sun from reaching us.
  4. Explain how an earthquake occurs. Ans: The crust part of earth is fragmented into many pieces called tectonic plates. These plates float over the hot magma below, and are therefore in relative motion to each other. As the plate moves collide, moves apart or slide over one another cause vibration that reach over surface of the