Question

The energy stored per unit volume in an electric field of strength $E$ volt per metre in a medium of dielectric constant $K\left(inJ{m}^{-3}\right)$ is

• A. $\frac{1}{2}{\epsilon }_0{E}^2$
• B. $\frac{1}{2}K{\epsilon }_0{E}^2$
• C. $\frac{1}{2}.\frac{{\epsilon }_0{E}^2}{K}$
• D. $\frac{1}{2}{K}^2{\epsilon }_0^{2}E$

Answer 1

Answer: (A)

$\frac{1}{2}{\epsilon }_0{E}^2$

The energy stored per unit volume in an electric field of strength $=EV/m$

dielectric constant $=K\left(inJ{m}^{-3}\right)$

Now,

$E=\frac{1}{2}{ϵ}_0{E}^2$ (Using in vacuum with electric energy density).