Question

Three copper wires of lengths and cross-sectional areas are (l, A), (2 l, A/2 ) and (l/2, 2A). Resistance is minimum in

(a) wire of cross-sectional area 2A

(b) wire of cross-sectional area A/2

(c) wire of cross-sectional area A

(d) same in all three cases

Answer 1

Correct option  (a) wire of cross-sectional area 2A

Explanation:

Three wires of lengths and cross-sectional

Therefore resistance of the wire will be minimum for III^rd wire.