Question:
A charge $Q$ is moving $\overline{\mathrm{dI}}$ distance in the magnetic field $\overrightarrow{\mathrm{B}}$. Find the value of work done by $\overrightarrow{\mathrm{B}}$.
Correct Option: , 3
Solution:
Since force on a point charge by magnetic field
is always perpendicular to $\overrightarrow{\mathrm{V}}[\overrightarrow{\mathrm{F}}=\mathrm{q} \overrightarrow{\mathrm{V}} \times \overrightarrow{\mathrm{B}}]$
$\therefore$ Work by magnetic force on the point charge is zero.