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 parallel plate capacitor after charging is kept connected to a battery and the plates are pulled apart with the help of insulating handles. Now which of the following quantities will decrease?

If charge on each plate of a parallel plate capacitor is $Q$ and the magnitude of electric field between the plates is $E$ then force on each plate of a parallel plate capacitor will be

How does a capacitor store energy ? And obtain the formula for the energy stored in the capacitor ?

If the plates of a parallel plate capacitor connected to a battery are moved close to each other, then

$A$. the charge stored in it, increases.

$B$. the energy stored in it, decreases.

$C$. its capacitance increases.

$D$. the ratio of charge to its potential remains the same.

$E$. the product of charge and voltage increases.

Choose the most appropriate answer from the options given below:

The energy stored in the electric field produced by a metal sphere is $4.5\, J$. lf the sphere contains $4\,\mu C$ charge, its radius will be.......$mm$ : [Take : $\frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9}\,N - {m^2}\,/{C^2}\, ]$