Question

A positive point charge $Q$ is kept (as shown in the figure) inside a neutral conducting shell whose centre is at $C$. An external uniform electric field $E$ is applied. Then

• A. force on $Q$ due to $E$ is zero.
• B. net force on $Q$ is zero
• C. net force acting on $Q$ and conducting shell considered as a system is zero
• D. net force acting on the shell due to $E$ is zero

Answer 1

Answer: (B), (D)

net force acting on the shell due to $E$ is zero

Charge will be induced on the surface of the conducting shell. On the inner surface of conducting shell induced charge is $-q$ and the Charge induced on outer surface of conducting shell is $+q$.

Since conducting shell is neutral i.e. $E=0$. So, force on it due to $E$ will be zero. So,Option (d) is correct

Inside the conducting shell electric field will always be zero. So net force acting on $Q$ is zero.

so, Option (b) is also correct.

Hence, options (b) and (d) are the correct answers.