Question

If $F$ is the force between two point charges submerged in a medium of dielectric constant $K$, then on withdrawing the medium, the force between the charges becomes

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

Answer 1

Answer: (B)

$F=\frac{1}{4 \pi \varepsilon_{0} K}\left(\frac{q_{1} q_{2}}{r^{2}}\right),$ with medium
$F^{\prime}=\frac{1}{4 \pi \varepsilon_{0}}\left(\frac{q_{1} q_{2}}{r^{2}}\right),$ without medium
$\Rightarrow \frac{F^{\prime}}{F}=K$ or $F^{\prime}=F K$