The earth's magnetic field at a given point is 0.5 `xx 10^(-5) Wb m^(2)` . This field is to be annulled by magnetic induction at the center of circular conducing loop of radius 5 . The current required to be flown in the loop is nearly

Options

A. 0.2 A
B. 0.4 A
C. `4` A
D. 40 A

Answer

A, D

Explanation

`B = (mu_(0) I)/(2r) rArr l = (2r B)/(mu_(0)) = (2xx 0.5 xx 0.5 xx 10^(-5) )/(4 pi xx 10^(-7)) = 0.4 `A