A charged particle enters a region in which a uniform electric field ( E ) and a…
PHYSICS · Multi-part · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism
Problem
A charged particle enters a region in which a uniform electric field E and a uniform magnetic field B are mutually perpendicular to each other as well as to the initial velocity v of the particle. The particle is observed to move through the region without any overall deflection from its initial straight-line path.
(i) State the mathematical expression for the total force experienced by a charge moving simultaneously in electric and magnetic fields.
(ii) Using suitable reasoning based on this force law, explain the qualitative condition that must be satisfied by the magnitudes of E, B and the speed v of the particle so that its trajectory remains undeviated.
(iii) Comment on whether this condition depends on (a) the sign of the charge and (b) the mass of the particle, giving reasons in each case.