Imp Questions For All Chapters – General Science Class 7
Static Electricity
Short Questions
1. What is static electricity?
→ Static electricity is the electric charge generated on an object due to friction.
2. Who discovered static electricity?
→ Thales, a Greek scientist, observed static electricity about 2500 years ago.
3. What are the two types of electric charges?
→ Positive charge (+) and Negative charge (-).
4. What happens when two objects with the same charge are brought near?
→ They repel each other.
5. What happens when two objects with opposite charges are brought near?
→ They attract each other.
6. What is meant by an electrically neutral object?
→ An object that has an equal number of positive and negative charges.
7. How is an electric charge created?
→ When two objects are rubbed together, negative charges transfer, making one object positively charged and the other negatively charged.
8. What is frictional electricity?
→ The electricity generated by rubbing two objects together is called frictional electricity.
9. Why do experiments with static electricity work better in winter?
→ Because in dry weather, static charges stay longer, while in humid conditions, they get absorbed by moisture.
10. What is an electroscope?
→ An electroscope is a device used to detect electric charge on an object.
11. Who named the electric charges as positive and negative?
→ Benjamin Franklin named them positive (+) and negative (-).
12. What happens when a charged balloon is brought near a wall?
→ It sticks to the wall due to the attraction of opposite charges.
Long Questions
1. What is a lightning conductor?
→ A device installed on buildings to protect against lightning strikes by directing the charge into the ground.
2. What is a lightning strike?
→ A sudden flow of electric charge between a cloud and the ground, causing light and sound.
3. Why do farmers place an iron rod in the ground during a thunderstorm?
→ It redirects the lightning into the ground, keeping them safe.
4. How are electric charges generated?
→ When two objects are rubbed together, negative charges transfer from one object to another, making one positively charged and the other negatively charged.
5. What is repulsion and attraction in static electricity?
→ Like charges repel (push away), and opposite charges attract (pull towards each other), as observed in rubbed rods.
6. Why is it dangerous to carry an umbrella during a thunderstorm?
→ The metal rod in the umbrella can attract lightning, which is dangerous and can cause injury.
7. What happens during a lightning strike?
→ Negative charges from clouds rush towards the ground, creating light, heat, and sound, sometimes damaging buildings and trees.
8. What are the characteristics of static electricity?
→ It is generated by friction, remains in one place, disappears in moist air, and can cause sparks or attraction.
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