Q. An electron and a proton travel with equal speed in the same direction at $90{^\circ}$ to a uniform magnetic field as this is switched on. They experience forces which are initially
A) Identical
B) Equal but in opposite direction
C) In the same direction and differing by a factor of about 1840
D) In opposite direction and differing by a factor of about 1840
Explanation
(b) Force on moving electron in perpendicular magnetic field
$= \ - e\left| \overrightarrow{V} \times \overrightarrow{B} \right|$
Force on moving proton in perpendicular magnetic field
= $e\ \left| \overrightarrow{V} \times \overrightarrow{B} \right|$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.