Q. A pulsar is a neutron star having magnetic field is $10^{12}$ G at its surface. The maximum magnetic force experienced by an electron moving with velocity 0.9 c is
A) 43.2 N
B) $4.32\ \times 10^{- 3}$ N
C) $4.32\ \times 10^{3}$ N
D) zero
Explanation
(b) ${\ F}_{\max}\ \ \ \ \ \ \ \ = evB$
$= \left( 1.6 \times 10^{- 19} \right) \times \left( 0.9 \times 3 \times 10^{8} \right) \times \left( 10^{8} \right)$
$= 4.32\ \times 10^{- 3}$ N
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.