Variation in electric potential is maximum if one goes

The potential difference between two parallel plates is $10^4 \,V$. If the plates are separated by $0.5 \,cm$, the force on an electron between the plates is

Some equipotential surfaces are shown in the figure below. The magnitude of the electric field will be $:-$ (in $V/m$)

The electric potential is given by $V = 4x^2 \ V$. What is the electric field at the point $(1 \ m, 0, 2 \ m)$?

The figure represents two equipotential lines in the $x-y$ plane for an electric field. The $x$-component $E_{x}$ of the electric field in the space between these equipotential lines is, (in $V/m$)

What is the potential gradient in a wire of resistivity $40 \times 10^{-8} \, \Omega \, m$ and cross-sectional area $8 \times 10^{-6} \, m^2$ when a current of $0.2 \, A$ flows through it?