A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel

Q.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

 

Answers:-

(d)    Resistance of a piece of wire is proportional to its length. A piece of wire has a resistance R. The wire is cut into five equal parts.
Therefore, resistance of each part =R/5
All the five parts are connected in parallel.
∴equivalent resistance (R’) is given as
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