An electron having mass m and kinetic energy E anter in uniform magnetic field B perpendiculaly, then its frequency will be

Among which the magnetic susceptibility does not depened on the temperature ?

Tangent galvanometer is used to measure

For a coil having L = 2 mH, current flow through it is $$I = {t^2}{e^{ - t}}$$ then, the time at which emf become zero