A circular arc of radius r carrying current ' I ' subtends an angle $\frac{\pi}{8}$ at its entre. The radius of a metal wire is uniform. The magnetic induction at the centre of circular arc is ( $\mu_0=$ permeability of free space)

The moment of inertia of uniform circular disc is maximum about an axis perpendicular to the disc and passing through point

An inductor coil of inductance $L$ is divided into two parts and both parts are connected in parallel. The net inductance is

If the momentum of a body of mass ' $m$ ' is increased by $20 \%$ then its kinetic energy increases by