Question 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:
(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. Hence, equivalent resistance (R’) is
given as
Therefore, the ratio R/R’ is 25.
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