Paragraph A special metal S conducts electricity without any resistance. A closed wire loop, made of S , does not allow any change in flux through itself by inducing a suitable current to generate a compensating flux. The induced current in the loop cannot decay due to its zero resistance. This current gives rise to a magnetic moment which in turn repels the source of magnetic field or flux. Consider such a loop, of

Step-by-step solution

For a super conducting loop, net flux passing through it will remain constant. ϕ total   i = ϕ total   f As area is same, therefore, μ 0 m 2 πr 3 = μ 0 I 2 a ⇒ I = a m πr 3 ⇒ I ∝ m r 3 The current carrying superconducting loop will also behave like a magnet, whose magnetic dipole moment is given by, m 1 = N I A = ( 1 ) a m πr 3 × π a 2 = m a 3 r 3 ⇒    m 1 ∝ m r 3 The repulsive force felt on the magnet will be F = K m 1 m