Q. A charged particle is moving in a uniform magnetic field in a circular path. The energy of the particle is tripled. If the initial radius of the circular path was $R,$ the radius of the new circular path after the energy is tripled will be
A) $\frac{R}{3}$
B) $\sqrt{3}\ R$
C) $3\ R$
D) $R/\sqrt{3}$
Explanation
(b) $E_{k} = \frac{1}{2}\frac{q^{2}B^{2}r^{2}}{m}ie,\ r \propto \sqrt{E_{k}}$
So, $r_{2} = r_{1}\sqrt{{E_{k}}_{2}/{E_{k}}_{1}}$= $R\sqrt{3} = \sqrt{3}\ R$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.