Question

The force acting between the two charges which are at a distance $d$ apart is $F$. If a copper plate of thickness $\frac{d}{2}$ is placed between them, then the effective force will be :

• A. $2F$
• B. $\frac{F}{2}$
• C. $0$
• D. $\sqrt{2}F$

Answer 1

The correct option is C $0$


The dielectric constant for any conductor, $K=\infty$

We, know that, the electrostatic force acting in a medium ican be written as,

$F_{\text{medium}}=\frac{F_{\text{vaccum}}}{K}$

In the given problem, the copper acts as a medium which is a very good conductor of electricity, so

$F_{\text{medium}}=\frac{F_{\text{vaccum}}}{\infty }=0$

Hence, option (c) is the correct answer.

Why this question? In the case of a conductor, $E=E_{ind}$ Therefore, Net electric field inside a conductor is always zero under static conditions.