Question

Assertion (A) : An electron and a proton enter with the same momentum p in a magnetic field B such that p ⊥ B. Then both describe a circular path of the same radius. Reason (R) : The radius of the circular path described by the charged particle (charge q, mass m) moving in the magnetic field B is given by r = mv/qB.

A particle of mass m and charge q is moving with a velocity v in a magnetic field B as shown in the figure. Show that it follows a helical path. Hence, obtain its frequency of revolution.

In a hydrogen atom, the electron moves in an orbit of radius 2 Å making 8 × 10¹⁴ revolutions per second. Find the magnetic moment associated with the orbital motion of the electron.

What is current sensitivity of a galvanometer ? Show how the current sensitivity of a galvanometer may be increased. "Increasing the current sensitivity of a galvanometer may not necessarily increase its voltage sensitivity." Explain.