$125$ identical charged small spheres coalesce to form a big charged sphere. If the electric potential on each small sphere is $60 \text{ mV}$, then the electric potential on the bigger sphere formed is: (in $\text{ V}$)

If four charges $+12 \text{ nC}, -20 \text{ nC}, +32 \text{ nC}$ and $-15 \text{ nC}$ are arranged at the four vertices of a square of side $\sqrt{2} \text{ m}$,then the net electric potential at the centre of the square due to these four charges is (in $\text{ V}$)

Two charges $+q$ and $-q$,each $1 \mu C$,are arranged as shown in the figure. If $x=2 \text{ cm}$ and $y=3 \text{ cm}$,then the potential difference $(V_A - V_B)$ is:

If a charged spherical conductor of radius $10\,cm$ has potential $V$ at a point distant $5\,cm$ from its centre,then the potential at a point distant $15\,cm$ from the centre will be

The electric potential at a distance $r$ outside a uniformly charged sphere (where $a$ is the radius of the sphere) is proportional to:

$A$ conducting sphere of radius $R$ is given a charge $Q$. The electric potential and the electric field at the centre of the sphere respectively are