Two wires of equal lengths are bent in the form of a square and a circular loop. They are suspended in a uniform magnetic field and same current is passed through them. Torque experienced by

An infinitely long straight conductor carrying current ' $I$ ' is bent into a shape as shown in figure. The radius of the circular loop is ' $r$ '. The magnetic induction at the centre of the loop at point ' O ' is

( $\mu_0=$ permeability of free space)

In the following figure magnitude of the magnetic field at the point $p$ is

A circular coil carrying current ' T ' has a radius ' $r$ ' and ' $n$ ' turns. The magnetic field along the axis of a coil at a distance ' $2 \sqrt{2} r$ ', from its centre is ( $\mu_0=$ permeability of free space, $n$ is very small)