Question

An infinite charged sheet has a surface charge density of 1 x 10^-7 Cm^-2 .How far apart are the equipotential surfaces whose potentials differ by 5volts?

Answer 1

Work out the electric field at any point, and use the fact that potential energy is \[-\int\limits_{\infty}^{a}F(x)dx\](i.e. a unit charge is dragged from infinity, parallel to the field lines, to a)

Answer 2

Use the fact that the electric field is the same everywhere (think of the electric flux through a cylinder on the plane).

Answer 3

Simpler when the field is constant which it is here - always for infinite plane
\[\Delta V = E*\Delta x\]

Answer 4

so 5 = E*Delta x
find E and then it will help find\[\Delta x\]

Answer 5

Yes, basically my integral simplifies to \[U=-Fx\] As F is not actually a function of x. Evaluated from infinity to a, or more simply the change in PE (from b to a), yields Mikael's result.