Q. An electron with (rest mass $m_{0})$ moves with a speed of 0.8$c$. Its mass when it moves with this speed is
A) $m_{0}$
B) $m_{0}/6$
C) $5m_{0}/3$
D) $3m_{0}/5$
Explanation
(c) $m = \frac{m_{0}}{\sqrt{1 - v^{2}/c^{2}}} = \frac{m_{0}}{\sqrt{1 - (0.8c)^{2}/c^{2}}} = \frac{5m_{0}}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.