Question

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R′, then the ratio R/R′ is –

 (a) 1/25 (b) 1/5 (c) 5 (d) 25

Answer 1

Resistance of a piece of wire is directly proportional to its length. If the piece of wire has a resistance R and the wire is cut into five equal parts. The resistance of each part = R/5 All the five parts are connected in parallel. Hence, equivalent resistance (R′) is given as

Hence, the option (d) is correct.