Question

If charge is distributed uniformly in xy plane with charge density to in first quardrant and $-\sigma$ in remaining three quadrants, then work done by electric field in moving a point charge q from $(0,0, d)$ to $(0,0,2 d)$ is:

• A. $\frac{-\sigma q}{4 \varepsilon_{0}} d$
• B. $\frac{\sigma q}{4 \varepsilon_{0}} d$
• C. $\frac{-\sigma q}{2 \varepsilon_{0}} d$
• D. $\frac{\sigma q}{\varepsilon_{0}} d$

Answer 1

Answer: (A)

As due to $2 $ part of plane
$E=\frac{-\sigma}{4 \varepsilon_{0}}$
$\Rightarrow W = q Ed$
$W =\frac{-\sigma qd }{4 \varepsilon_{0}}$