Exercise

Consider two concentric spherical metal shells of radii $r_1$ and $r_2 \left(r_2>r_1\right)$. If the outer shell has a charge $q$ and the inner one is grounded, the charge on the inner shell is,

Lightning rods are made of-

What is meant by frictional electricity? Describe its origin.

State and explain: the principle of superposition as applied to electrostatic forces on a charge due to a number of charges.

For the torque to be maximum on a dipole placed in an electric field angle between $\overrightarrow{P}$ and $\overrightarrow{E}$ must be 

On placing a dipole in a uniform electric field it is acted upon by a

Explain the unstable equilibrium condition of a dipole in an electric field.

The force of attraction between $+5 \mathrm{\mu C}$ and $–5 \mathrm{\mu C}$ charges kept at some distance apart is $9 \mathrm{N}$. When the two charges are made to contact and then separated again by the same distance the force acting between them becomes