potential due to point charges: details below?

Question

(a) What is the electric potential a distance of 2.5 * 10^-15m away from a proton? (b) What is the electric potential energy of a system that consists of two protons 2.5*10^-15m apart -- as might occur inside a typical nucleus?

Answer 1

a) The equation you need to use is:

V = kq/r

where k = 9x10^9, q is the charge of a proton and r is the distance away from the proton.

b) This problme uses the equation:

U = kq1q2/r = ke^2/r where e is the unit charge