Q. An electron with mass $m,$ velocity $v\ and\ charge\ e$ describes half a revolution in a circle of radius $r$ in a magnetic field $B$, will acquire energy equal to
A) 1/2$mv^{2}$
B) 1/4$mv^{2}$
C) $\pi rBev$
D) zero
Explanation
(d) As energy can neither be created nor destroyed, therefore, its energy will remain constant and will acquire no extra energy.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.