$A$ particle $A$ has charge $+q$ and particle $B$ has charge $+4q$,with each of them having the same mass $m$. When allowed to fall from rest through the same electric potential difference $V$,the ratio of their speeds $\frac{v_A}{v_B}$ will be:

The electric potential on the surface of a charged spherical conductor of radius $5 \,cm$ is $200 \,V$. The work done in moving a charge of $+5 \,C$ from a point $A$ to another point $B$ situated at distances of $15 \,cm$ and $10 \,cm$ respectively from the centre of the sphere is (in $\,J$)

Two conducting hollow spheres of radii $R$ and $3R$ are found to have $Q$ charge on their outer surfaces when both are connected with a long wire. $A$ charge $q'$ is kept at the centre of the bigger sphere. Which of the following is true?

Two spheres $A$ and $B$ of radius $a$ and $b$ respectively are at the same electric potential. The ratio of the surface charge densities of $A$ and $B$ is

$A$ point charge $q$ is surrounded symmetrically by six identical charges each of magnitude $q$ at a distance $r$ as shown in the figure. How much work is done by the forces of electrostatic repulsion when the point charge $q$ at the centre is moved to infinity?

The value of the electric potential at a point due to a point charge is: