question_answer 1)

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:

Resistance of each one of the five parts   Resistance of five parts connected in parallel is given by   or              or                                   Thus, (d) is the correct answer.