Question

Q. A piece of wire of resistance R is cut into five equal parts. These parts (1)
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

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Answer 1

Answer:

Wire is cut into 5 equal parts. Since all dimensions are same for pieces, Resistance of each wire is equal and has a value = R/5. Resistance is proportional to length of wire and inversely proportional to area of cross-section. IF length is 1/5th, then Resistance is also 1/5 th of original value.

option b is correct answer

I hope that you found it useful

Answer 2

Explanation:

number of resistance = 5

equivalent resistance of the five resistance when connected in parallel = R/n = R/5

now equivalent resistance of the five resistance when connected in series= Rn = 5R

so ratio of equivalent resistance of five resistance when in series & equivalent resistance of the five resistance when connected in parallel

= 5R ÷ R/5

= 5R × 5/R

= 25R/R

= 25/1