Physics
Describe with the aid of a diagram some form of a fuse, which is used in the electric lighting circuit of a house. Give two reasons why a fuse must not be replaced by an ordinary copper wire.
Answer
The figure below shows one of the most common fuse arrangement in which the the fuse wire F is stretched between the two metallic terminals T1 and T2 in a porcelain holder (since porcelain is an insulator of electricity). This holder fits into a porcelain socket having two metallic terminals to each of which the live wire of the circuit is connected. Thus, fuse wire gets connected in the live wire.
A copper wire is unsuitable for use as the fuse wire because:
- It has a high melting point (approx 1080 °C).
- Normally a thick wire is available which will not melt even if the current exceeds it's safe limit.
Related Questions
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(a) Name the switch/switches to be closed so as to light all three lamps.
(b) How are then the lamps connected : in series or in parallel.
(a) What is the purpose of a switch in a circuit?
(b) Why is the switch put in the live wire?
(c) What precaution do you take while handling a switch?
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