Question

There is an electric field $E$ in $x-$ direction. If the work done by electric force on moving a charge of $0.2\text{C}$ through a distance of $2\text{m}$ along a line making an angle ${60}^{\circ }$ with $x-$ axis is $4\text{J}$, then what is the value of $E$?
(Neglect gravity)

• A. $10\text{N/C}$
• B. $15\text{N/C}$
• C. $20\text{N/C}$
• D. $25\text{N/C}$

Answer 1

The correct option is C $20\text{N/C}$

Given:
$q=0.2\text{C};d=2\text{m};W=4\text{J}$

Here, $E$ is the electric field in $x-$ direction.


We know that, work done by a force is defined as,

$W=\overrightarrow{F}.\overrightarrow{d}=Fd\cos \theta$

$\Rightarrow W=qEd\cos \theta (\because F=qE)$

$\Rightarrow 4=0.2\times E\times 2\times \cos {60}^{\circ }$

$\Rightarrow E=20\text{N/C}$

Hence, option $\left(c\right)$ is the correct answer.