Question

A 5.40 uF parallel-plate, air capacitor has a plate separation of 3.50 mm and is charged to a potential difference of 480 V. Calculate the energy density the region between the plates.

Answer 1

Answer:

Energy density = 0.0831 J/m³

Explanation:

Energy density of a capacitor is given by the expression

        $u=\frac{1}{2}\epsilon E^2$

We have electric field ,

              $E=\frac{V}{d}=\frac{480}{3.5\times 10^{-3}}=1.37\times 10^5V/m$

Here there is no dielectric

So energy density,

         $u=\frac{1}{2}\epsilon_0 E^2=\frac{1}{2}\times 8.85\times 10^{-12} \times (1.37\times 10^5)^2=8.31\times 10^{-2}=0.0831 J/m^3$

Energy density = 0.0831 J/m³