Q. The mean electric energy density between the plates of a charged capacitor is (here $q =$ charge on the capacitor and $A =$ area of the capacitor plate)
A) $\frac{q^{2}}{2\varepsilon_{0}A^{2}}$
B) $\frac{q}{2\varepsilon_{0}A^{2}}$
C) $\frac{q^{2}}{2\varepsilon_{0}A}$
D) None of the above
Explanation
(a) Energy density $= \frac{1}{2}\varepsilon_{0}E^{2} = \frac{1}{2}\varepsilon_{0}\left( \frac{\sigma}{\varepsilon_{0}} \right)^{2} = \frac{\sigma^{2}}{2\varepsilon_{0}} = \frac{q^{2}}{2\varepsilon_{0}A^{2}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.