Question

Two fixed charges separated by a distance $d$ experience a force $F$. A dielectric medium of thickness $\frac{d}{4}$ and dielectric constant $4$ is introduced in the space between them. Find the new force between the charges.

• A. $\frac{F}{4}$
• B. $\frac{F}{3}$
• C. $F$
• D. $\frac{16F}{25}$

Answer 1

The correct option is A $\frac{F}{4}$

The force between the 2 charged particles is inversely proportional to the permittivity.

Therefore if the permittivity increases by 4 times, then obviously the force decreases by 4 times.

Therefore the new force is given by, $\frac{F}{4}$