Electrostatics Question 113
Question: 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) [MP PET 2002]
Options:
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
Show Answer
Answer:
Correct Answer: A
Solution:
Energy density $ =\frac{1}{2}{\varepsilon _{0}}E^{2}=\frac{1}{2}{\varepsilon _{0}}{{( \frac{\sigma }{{\varepsilon _{0}}} )}^{2}}=\frac{{{\sigma }^{2}}}{2{\varepsilon _{0}}}=\frac{q^{2}}{2{\varepsilon _{0}}A^{2}} $
