1. Fill in the blanks :
(a) A device that is used to break an electric circuit is called __switch_____________.
(b) An electric cell has ____two___________ terminals.
2. Mark 'True' or 'False' for the following statements:
(a) Electric current can flow through metals. ( True)
(b) Instead of metal wires, a jute string can be used to make a circuit. ( False)
(c) Electric current can pass through a sheet of thermo Col. ( False)
3. Explain why the bulb would not glow in the arrangement is shown in Fig. 12.13.
Answer:
- Plastic is not a conductor, here plastic material ( tester cover) used in the circuit wire, which is why the bulb will not glow.
4. Complete the drawing shown in Fig 12.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.
Answer:
Yes, will glow.
5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches
built into them.
Answer:
- An electric switch is used to complete or break the electric circuit.
- Electric gadgets example; Fridge, AC,
6. Would the bulb glow after completing the circuit shown in Fig. 12.14 if instead of a safety pin we
use an eraser?
Answer:
- Eraser is not the conductor of electricity, the bulb will not glow.
7. Would the bulb glow in the circuit shown in Fig. 12.15? Using the "conduction tester" on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.
Answer:
- Yes, the conduction tester is a good conductor, it will complete the circuite.
9. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Answer:
- rubber gloves are a bad conductor. They use to prevent electric shock.
10. The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?
Answer:
- Plastic and rubber are bad conductors of electricity. It helps to prevent the electric shock while repairing.
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