Question

There is an electric field E in the +x-direction. If the work done by the electric field in moving a charge 0.2 C through a distance of 2m along a line making an angle of 60${}^o$ with the x-axis is 1.0 J, what is the value of E in NC${}^{-1}$?

Answer 1

$\text{Given :}W=1.0J,q=0.2C,d=2m,\theta ={60}^o$

$\text{Step 1 : Work done by the electric field}$

$W=\overrightarrow{F}\cdot \overrightarrow{d}=Fd\cos \theta =qEd\cos \theta$ $....\left(1\right)$ $($Since $F=qE)$

$\text{Step 2 : Substituting the values}$

Or, $1=0.2\times E\times 2\cos {60}^o$

Or, $E=\frac{1}{0.2\times 2\cos {60}^o}=\frac{1}{0.2\times 2\left(1/2\right)}=5N{C}^{-1}$