class 7 revision question of electric current and simple circuits.

    ELECTRIC CURRENT AND SIMPLE CIRCUITS 
                  REVISION QUESTION



1. Electric current is the flow of
 a. Proton b. Electron c. Neutron d. Nucleus
 2. Which of the following materials is a conductor?
 a. Silver b. Plastic c. Cloth d. Rubber
 3. A device which prevents or allow the current to flow through it a. Motor b. Conductor c. Switch d. Terminal
 4. When two or more cells are joined together it forms a
 a. Dynamo b. Transistor c. Battery d. Insulator

5. Fill in the blanks.
 a. ----------- is the best conductor of electricity.
 b. A -------------- is used to protects appliances from damage due to excessive current.
c. A short occurs when a -------------- comes in direct contact with neutral wire.
 d. Live wire is covered with ------------- coloured insulation. 
e. Connecting many appliances with single circuit may lead to -------------. 
6. What is short-circuiting? How it occurs? 
7. What is electromagnetic induction? Write its application.
 8. Write 3 application of electromagnet. 
9. Name the following 
a. Device used to measure the amount of current.
 b. A piece of thin wire of high resistance, used in electric bulb.
 c. A device which offers resistance to an electric current.
 d. A number of cells joined together.
 e. Safety device used to protect us from electric shocks.

10. What is electromagnet? Write its two applications.
 11. What is electric bell? Name its main components. 
12. What is difference between open and closed circuit?

13. What is electromagnetic effect of electric current? 
14. What is electric current? How its flows? 
15. Write difference between electromagnet and permanent magnet? 
16. Rearrange the jumbled letters to form meaningful words related to Electricity. 
a. RECURNT
 b. BYATTRY
 c. UFSE
 d. CTROLENETMAG 
e. ICRITUC