Question

A current flows in a wire of circular cross-section with the free electrons travelling with a mean drift velocity v. If an equal current flows in a wire of the same material but of twice the radius,what is the new mean drift velocity (a)v/4(b)v/2(c)2v(d)4v

Answer 1

radius*2 means area*4, so v/4

Answer 2

V/4

Answer 3

V/2