Question

In space a uniform electric field exists in $x-$ direction. If the work done by external agent in moving a charge of $0.2\text{C}$ through a distance of $2\text{m}$ , slowly along the line making an angle of ${60}^{\circ }$ with $x-$ direction is $4\text{J}$, then the magnitude of the electric field $E$ is-

• A. $\sqrt{3}{\text{NC}}^{-1}$
• B. $4{\text{NC}}^{-1}$
• C. $5{\text{NC}}^{-1}$
• D. $20{\text{NC}}^{-1}$

Answer 1

The correct option is D $20{\text{NC}}^{-1}$



As we know,

$W=\overrightarrow{F}.\overrightarrow{S}$

$W=qE\times S\times \cos \theta$

Substituting the data given in the question,

$4=0.2\times E\times 2\times \frac{1}{2}$

$E=\frac{4}{0.2}=20{\text{NC}}^{-1}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(D\right)$ is the correct answer.