Question

From what distance should an electron of energy $E$ be fired on the change metal plate of charge density $-\sigma$ so that it velocity becomes zero just before its reaches the plate-

• A. $\sigma eE/{\epsilon }_0$
• B. $2\sigma eE/{\epsilon }_{0}e$
• C. $\sigma eE/2{\epsilon }_0$
• D. ${\epsilon }_{0}E/\sigma e$

Answer 1

The correct option is D ${\epsilon }_{0}E/\sigma e$

Force due to metal plate is

F=q.E &

Potential Energy U =-W=-F.d