Question

Obtain an expression for the torque τ acting on a current carrying loop in a uniform magnetic field B. Draw the necessary diagram.

A current carrying circular loop of magnetic moment M⃗ is suspended in a vertical plane in an external magnetic field B⃗ such that its plane is normal to B⃗. The work done in rotating this loop by 45° about an axis perpendicular to B⃗ is closest to :

Assertion (A) : The torque acting on a current carrying coil is maximum when it is suspended in a radial magnetic field. Reason (R) : The torque tends to rotate the coil on its own axis.

Assertion (A) : The deflecting torque acting on a current carrying loop is zero when its plane is perpendicular to the direction of magnetic field. Reason (R) : The deflecting torque acting on a loop of magnetic moment m⃗ in a magnetic field B⃗ is given by the dot product of m⃗ and B⃗.