Question

nichrome wire of length 1 and radius R has resistance of 10 ohm how would the resistance of the wire change when only length of wire doubled

Answer 1

Given that the nichrome wire has length 1 and radius R with resistance of 10 ohm, the resistance of wire depends on the length.

Theoretically, length of the wire is directly proportional to the resistance of the wire.

So, the resistance of the wire after length of the wire is doubled will be 20 ohms.

Answer 2

Answer:

So when diameter is doubled, resistance becomes one-fourth of the original i.e., R = 2.5 Ω

(b) Elements of heating devices are made up of alloys because :

(1) They have high melting points.

(2) They have high resistances, so when even a small magnitude of current passes through them, they get heated up enormously.

(3) They do not oxidise readily.