A Wire of Radius 0

Multiple Choice

A wire of radius 0.6 cm carries a current of 10 A that is uniformly distributed over its cross section.Calculate the magnetic field strength at r = 0.2 cm divided by that at r = 0.4 cm.

A) 1.0
B) 0.75
C) 0.50
D) 2.0
E) 3.0