Problem 25.

A potential difference of 10 kV is established between parallel plates in air.

(a) If the air becomes electrically conducting when the electric field exceeds , what is the minimum separation of the plates?

(b) When the separation has the minimum value calculated in part (a), what is the surface charge density on each plate?

Solution

(a) The potential difference is related to the electric field by the following equation:

From this equation we can find the minimum distance:

(b) The electric field between two parallel plates has the following form

Then