Find the magnetic moment of a thin round loop with current if the radius of the loop is equal to `R = 100 mm` and the magnetic induction at its centre is equal to `B = 6.0 mu T`.

Explanation

Magnetic field at centre
`B = (mu_(0)i)/(2R) rArr i = (2RB)/(mu_(0))`
Magnetic moment of loop
`M = iA = i. pi R^(2) = (2RB)/(mu_(0))pi R^(2)`
`= (2 BR^(2))/(mu_(0)//pi) = (2 xx 6 xx 10^(-6) xx (0.1)^(3))/(4 xx 10^(-7))`
`= 3 xx 10^(-2) A.m^(2)`