Three charged concentric nonconducting shells are given as shown in the figure. Find the potential at point $A$.

Two equal positive point charges are kept at points $A$ and $B$. What happens to the electric potential while moving from $A$ to $B$ along the straight line connecting them?

Two electric charges $12\,\mu C$ and $-6\,\mu C$ are placed $20\, cm$ apart in air. There will be a point $P$ on the line joining these charges and outside the region between them,at which the electric potential is zero. The distance of $P$ from the $-6\,\mu C$ charge is.......$m$.

An electron (charge = $1.6 \times 10^{-19} \text{ C}$) is accelerated through a potential of $100,000 \text{ V}$. The energy acquired by the electron is:

Two concentric hollow spherical conductors of radii $R$ and $2R$ have charges $Q$ and $-Q$ respectively. Find the electric potential at a distance of $\frac{3R}{2}$ from the centre. $\left[K=\frac{1}{4\pi\varepsilon_0}\right]$

Draw a graph of $V$ versus $r$ for a uniformly charged spherical shell of radius $R$.