Twenty seven drops of same size are charged at $220\, \mathrm{~V}$ each. They combine to form a bigger drop. Calculate the potential of the bigger drop. (In $\mathrm{~V}$)

Electric charges having same magnitude of electricicharge $q$ coulombs are placed at $x=1 \,m , 2 \,m , 4 \,m$, $8 \,m$……. so on. If any two consecutive charges have opposite sign but the first charge is necessarily positive, what will be the potential at $x=0$ ?

A uniform electric field of $400 \,v/m$ is directed $45^o$ above the $x$ – axis. The potential  difference $V_A – V_B$ is -…..$V$

Two equal positive point charges are kept at points $A$ and $B$ . The electric potential, while moving from $A$ to $B$ along straight line

Three concentric metal shells $A, B$ and $C$ of respective radii $a, b$ and $c (a < b < c)$ have surface charge densities $+\sigma,-\sigma$ and $+\sigma$ respectively. The potential of shell $B$ is