The work done to take an electron from rest where potential is $-60\, V$ to another point where potential is $-20\, V$ is given by.....$eV$.

$A$ proton is accelerated through $50,000 \, V$. Its energy will increase by

$A$ hollow metal sphere of radius $5\,cm$ is charged such that the potential on its surface is $10\,V$. The potential at a distance of $2\,cm$ from the centre of the sphere is.......$V$.

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 $P$ midway between the two negative charges is:

$A$ neutral spherical copper particle has a radius of $10 \,nm$ $(1 \,nm = 10^{-9} \,m)$. It gets charged by applying the voltage,slowly adding one electron at a time. Then,the graph of the total charge on the particle versus the applied voltage would look like:

$A$ ball of mass $1\, g$ and charge $10^{-8}\, C$ moves from a point $A$,where the potential is $600\, V$,to a point $B$,where the potential is $0\, V$. The velocity of the ball at point $B$ is $20\, cm/s$. The velocity of the ball at point $A$ will be: