Problem 5.196

A certain substance is placed in a longitudinal magnetic field of a solenoid located between two Polaroids. The length of the tube with substance is equal to \(l=30 \mathrm{~cm} .\) Find the Verdet constant if at a field strength \(H=56.5 \mathrm{kA} / \mathrm{m}\) the angle of rotation of polarization plane is equal to \(\varphi_{1}=+5^{\circ} 10^{\prime}\) for one direction of the field and to \(\varphi_{2}=-3^{\circ} 20^{\prime},\) for the opposite direction.