Question

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

• A. $5\frac{N}{C}$
• B. $20\frac{N}{C}$
• C. $\sqrt{3}\frac{N}{C}$
• D. $4\frac{N}{C}$

Answer 1

The correct option is B $20\frac{N}{C}$


Given that
Work done $W=4J$
charge $q=0.2C$
displacement $s=2m$
angle of motion with the electric field $\theta ={60}^{\circ }$
We know that work done is given by
$W=F.s\Rightarrow W=Fs\cos \theta \Rightarrow W=qEs\cos \theta$
Putting values we get
$\Rightarrow W=0.2\times E\times 2\times \cos {60}^{\circ }$
$\Rightarrow E=20N/C$