A superconducting loop of radius R has self-inductance L . A...

Initially, the current was zero, so self-induced flux was also zero. Now when we rotate the loop, the change in flux is

$\Deltaϕ = 2\piR^{2} \times B$

Finally, to maintain the same zero flux, the current in the superconducting loop will be such that the flux due to induced current will negative of the flux due to external field

$L \times i = 2\piR^{2} \times B$.

$i = \dfrac{2\piR^{2} \times B}{L}$