Question

An air-filled capacitor stores a potential energy of 6 mJ due to its charge. It is accidentally filled with water in such a way as not to discharge its plates. How much energy does it continue to store after it is filled? (The dielectric constant for water is 78 and for air it is 1.0006.

Answer 1

Answer:

The potential energy in the water will be 0.0769 mJ

Explanation:

We know that energy stored in the capacitor due to charge is given by $U=\frac{Q^2}{2C}$

From the relation we can see that potential energy is inversely proportional to the capacitance

And we also know that capacitance is directly proportional to the dielectric constant

So the new potential energy will be $=\frac{6}{78}=0.0769mJ$

So the potential energy in the water will be 0.0769 mJ