Wire I and wire II are made of the same material. Wire II has twice the diameter and twice the length of wire I. If wire I has resistance R, wire II has resistance

(A) R/8 

(B) R/4 

(C) R/2 

(D) R 

(E) 2R

4 views

1 Answers

The correct option is: (C) R/2 

Explanation:

R = ρL/A ∝ L/d2 where d is the diameter. RII/RI = LII/dII2 ÷ LI/dI2 = (2LI)dI2/[LI(2dI)2] = ½

4 views