A particle having charge $q$ and mass $m$ is projected with velocity $v=2\hat{\mathrm{i}}-3\hat{\mathrm{j}}$ in a uniform electric field $E=E_0\hat{\mathrm{j}}$. Change in momentum $\left|\mathrm{\Delta }p\right|$ during any time interval $t$ is given by

Two conducting plates $A$ and $B$ each having large surface area $S$ (on one side) are placed parallel to each other. The plate $A$ is given a charge $q$, while the plate $B$ is neutral. Then, the electric field at a point in between the plates is:

A thin, metallic spherical shell contains a charge $Q$ on it. A point charge $q$ is placed at the centre of the shell and another charge $q_1$ is placed outside it as shown in figure. All three charges are positive. The force on the charge at the centre is

A thin, metallic spherical shell contains a charge $Q$ on it. A point charge $q$ is placed at the centre of the shell and another charge $q_1$ is placed outside it as shown in the figure. All three charges are positive. The force on the central charge due to the shell is: