A toroid of n turns mean radius R and sectional radius a carriers current I it is placed on a horizontal table taken as x-y plane its magnetic moment m

Options

A. is non zero and points in the z directin buy symmetry
B. points along the axis of the tortoid
C. is zero otherwise there would be a field falling as `(1)/(r ^(3))` at alrge distance outside the toroid
D. is pointing radially outwards

Answer

C