A wire of given material having length l and area of cross-section A, has a resistance of 2 Ω. Find the resistance of another wire of same material having length 2l and are of cross-section A/2.

Question

Philoid · Accepted Answer

Given

Resistance (R) = 2Ω

Area of cross-section = A

Length = l

We know that

⇒ (1)

New Area = A/2

New Length = 2l

New Resistance = R’

⇒

⇒ from (1).

Hence the new resistance will be four times the previous resistance i.e. 8Ω.