Question

If the area of cross-section of a resistance wire is halved, then its resistance becomes:

(a) one-half
(b) 2 times
(c) one-fourth
(d) 4 times

Answer 1

(b) 2 times
The resistance of a conductor is inversely proportional to its area of cross-section, i.e. R α 1 / A. So, when the area of cross-section of a resistance wire is halved, its resistance will increase by two times.