Magnetic induction at the centre of a circular loop of area `pim^(2)` is 0.1 T. The magnetic moment of the loop is (`pi_(0)=` permeability of air)

Options

A. `(0.1pi)/(mu_(0))`
B. `(0.2pi)/(mu_(0))`
C. `(0.3pi)/(mu_(0))`
D. `(0.4pi)/(mu_(0))`

Answer

B

Explanation

Magnetic induction at the centre of circular loop
`B=(mu_(0)ni)/(2r)`
Magnetic moment of the loop, `m=niA=(2BrA)/(mu_(0))`
`implies M=(2xx0.1xxpixx(1)^(2))/(mu_(0))`
`therefore M=(0.2pi)/(mu_(0))`