electrostatics Questions

Two hollow conducting spheres of radii $R_1$ and $R_2$ ($R_1\gg R_2$) have equal charges. The potential would be:

The angle between the electric lines of force and the equipotential surface is:

Two point charges $-q$ and $+q$ are placed at a distance of $L$, as shown in the figure. The magnitude of electric field intensity at a distance $R$ ($R\gg L$) varies as:

A capacitor of capacitance $C=900\text{pF}$ is charged fully by $100\text{V}$ battery. Then the battery is disconnected and the capacitor is connected to another uncharged capacitor of capacitance $C=900\text{pF}$. The electrostatic energy stored by the system is: