Three rings, each having equal radius R, are placed mutually perpendicular to each other and each having its centre at the origin of co-ordinate system. If current I is flowing through each ring, then the magnitude of the magnetic field at the common centre is

Options

A. `(pi/2,1/3)`
B. `(pi/2,2/3)`
C. `(pi,1/3)`
D. `(pi,2/3)`

Answer

D

Explanation

`2piR = 2pi therefore R=1`
`y_(CM) = (m xx 0 + m xx 1 + mxx1)/(m+m+m) = 2/3`
`x_9CM) = (m(pi)+ m(0) + m(2pi))/(m + m + m) = pi`