Question

The magnetic force acting on a charged particle of charge$-2\mu C$ in a magnetic field of 2T acting in y-direction, when the particle velocity is $(2\check{i}+3\check{j})$ $\times {10}^{6}m{s}^{-1}$ is :

• A. 8 N in Z-direction
• B. 4 N in Z-direction
• C. 8 N in y-direction
• D. 4 N in Y-direction

Answer 1

The correct option is A 8 N in Z-direction

Force on a moving charge in magnetic field $=q(\overrightarrow{v}\times B)$

$\Rightarrow \overrightarrow{F}=-2\times {10}^{-6}(2\hat{i}+3\hat{j})\times 2\hat{j}\times {10}^6$

$\Rightarrow \overrightarrow{F}=-2\times {10}^{-6}(2\hat{i}\times 2\hat{j})\times {10}^6$

$\Rightarrow \overrightarrow{F}=-8\hat{k}N$

Therefore, A is correct option.