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:

The resistance of wire is R. This wire is cut into five equal pieces. The resistance of each piece of the wire will be R1, R2, R3, R4 and R5 respectively. Now, when these five pieces are connected in parallel, the equivalent resistance for the combination is R’. We can write,

Thus, the correct answer is: Option (d)