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 $50\, V$

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.

Three infinitely long linear charges of charge density $\lambda $ , $\lambda $ and $-2\lambda $ are placed in space. A point in space is specified by its perpendicular distance $r_1 , r_2 $ and $ r_3$ respectively from the linear charges. For the points which are equipotential

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

Draw an equipotential surface for a point charge.

Draw an equipotential surface of two identical positive charges for small distance.