Question

An infinite long plate has surface charge density $sigma$ As shown in the figure, a point charge q is moved from A to B Net work done by electric field is:

Answer 1

we know that the work done on a charge is given by:

$W=Vd$ [V is the voltage/potential difference and d is the distance covered by charge]

The potential difference due to the charge in the electric field is given by:

$V=qE$

therefore, it can be written as:

$W=qE.d$

Now $E=\frac{\sigma }{2}ϵ$

Hence $W=q\times \sigma \times \frac{(X_1-X_2)}{2ϵ}$