Q. A charged particle with charge $q$ enters a region of constant, unform and mutually orthogonal fields $\overrightarrow{E}$ and $\overrightarrow{B}$ with a velocity $\overrightarrow{v}$ perpendicular to both $\overrightarrow{E}$ and $\overrightarrow{B}$, and comes out without any change in magnitude or direction of $\overrightarrow{v}$. Then
A) $\overrightarrow{v} = \overrightarrow{E} \times \overrightarrow{B}/B^{2}$
B) $\overrightarrow{v} = \overrightarrow{E} \times \overrightarrow{B}/B^{2}$
C) $\overrightarrow{v} = \overrightarrow{E} \times \overrightarrow{B}/E^{2}$
D) $\overrightarrow{v} = \overrightarrow{B} \times \overrightarrow{E}/E^{2}$
Explanation
(a) $\overrightarrow{v} \times \overrightarrow{B} = - \overrightarrow{E}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.