The electric potential at a distance of $R/2$ from the center of a charged conducting sphere of radius $R$ is .......

For a point charge,the electric potential and electric field at a given point are $600 \, V$ and $200 \, N/C$ respectively. The magnitude of the point charge is ......... $\mu C$.

Write expressions for electric potential due to a continuous distribution of charges.

$A$ particle $A$ has a charge of $+q$ and a particle $B$ has a charge of $+9q$. Both particles have the same mass $m$. If both particles are released from rest through the same potential difference,the ratio of their speeds will be .......

Eight charges,each of magnitude $q$,are placed at the vertices of a cube placed in a vacuum. The electric potential at the centre of the cube due to this system of charges is . . . . . . . ($\varepsilon_0 = $ permittivity of vacuum,$a = $ length of each side of the cube.)

Four electric charges $+q, +q, -q$, and $-q$ are placed in order at the corners of a square of side $2r$. The electric potential at a point midway between the two negative charges is