Question

What is K in capacitance?

Answer 1

1. The charge on the capacitor (Q) is directly proportional to the potential difference (V) between the plates.
   $$\begin{gathered} \mathrm{Q}\propto \mathrm{V} \\ \mathrm{Q}=\mathrm{CV} \end{gathered}$$
   where, The constant of proportionality $\mathrm{C}$ is termed as the capacitance of the capacitor.
2. The unit of capacitance is $\mathrm{Farad}\left(\mathrm{F}\right)$
3. $\mathrm{K}$ is the dielectric constant in the capacitance.
4. The capacitance relation for parallel plate capacitor:
   $\mathrm{C}=\frac{{\mathrm{K\epsilon }}_0\mathrm{A}}{\mathrm{d}}$
   $\mathrm{C}$ is the capacitance of the parallel plate capacitor, $\mathrm{K}$ is the dielectric constant, ${\mathrm{\epsilon }}_0$ is the permittivity of the free space, $\mathrm{A}$ is the area of parallel conducting plates,$\mathrm{d}$ is the separation between parallel conducting plates
5. K is the ratio of the permittivity of the substance to the permittivity of the free space.

Hence, K is the dielectric constant.