Question

A charged particle moves through a magnetic field in a direction perpendicular to it. Then the

• A. Speed of the particle remains unchanged
• B. Direction of the particle remains unchanged
• C. Acceleration remains unchanged
• D. Velocity remains unchanged

Answer 1

The correct option is A Speed of the particle remains unchanged

[]We know that $Force$ on a charged prtice $q$ due to magnetic field $\overrightarrow{B}$ is given by

$\overrightarrow{F}=q(\overrightarrow{V}\times \overrightarrow{B})$ where $\overrightarrow{V}$ is the velocity of charged particle

Thus,from the expression of force it is clear that $\overrightarrow{F}$ is perpendicular to both $\overrightarrow{V}and\overrightarrow{B}$

As $Force$ is perpendicular to $Velocity,$ this implies $Speed$ will not be changed only $Direction$ will be changed

Thus $Speed$ will remain unchanged

answer A