If a unit positive charge is taken from one point to another over an equipotential surface, then

Two point charges of magnitude $+q$ and $-q$ are placed at $\left( { - \frac{d}{2},0,0} \right)$ and $\left( {\frac{d}{2},0,0} \right)$, respectively. Find the equation of the equipotential surface where the potential is zero.

What is an equipotential surface ? Draw an equipotential surfaces for a

$(1)$ single point charge

$(2)$ charge $+ \mathrm{q}$ and $- \mathrm{q}$ at few distance (dipole)

$(3)$ two $+ \mathrm{q}$ charges at few distance

$(4)$ uniform electric field.

An infinite non-conducting sheet has a surface charge density $\sigma  = 0.10\, \mu C/m^2$ on one side. How far apart are equipotential surfaces whose potentials differ by $50\, V$

Which of the following figure shows the correct equipotential surfaces of a system of two positive charges?

The equation of an equipotential line in an electric field is $y = 2x$, then the electric field strength vector at $(1, 2)$ may be