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) \(\frac{1}{25} \)
• (b) \(\frac{1}{5} \)
• (c) 5
• (d) 25

(d)25

Resistance of a piece of wire is proportional to its length. The given piece of wire has a resistance R. The wire is cut into five equal parts. Therefore, resistance of each part is
All the five parts are connected in parallel. Hence, equivalent resistance (R') is given as