Q. An electric field of intensity $6 \times 10^{4}\ Vm^{- 1}$ is applied perpendicular to the direction of motion of the electron. A magnetic field of induction $8 \times 10^{- 2}\ Wm^{- 2}$ is applied perpendicular to both the electric field and direction of motion of the electron. What is the velocity of the electron if it passes undeflected?
A) $7.5 \times 10^{5}\ ms^{- 1}$
B) $7.5 \times 10^{- 5}\ ms^{- 1}$
C) $48 \times 10^{- 2}\ ms^{- 1}$
D) It is never possible
Explanation
(a) $v = E/B = 6 \times 10^{4}/8 \times 10^{- 2} = 7.5 \times 10^{5}ms^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.