What is the electric potential relative to infinity at a distance of 10-11 m from a?

Question

What is the electric potential relative to infinity at a distance of 10^-11 m from a proton?

Answer: 144 V

Answer 1

A proton is a point charge so you can use the expression for the electric fielt

E = q/(4piEr^2) (where E is epsilon really)

V = -integralfrom infinity to 10^-11m of E.dr

V = [q/(4piEr)] at x = 10^-11, minus that at infinity. V at infinity = 0

q = e = 1.602x10^-19C

So V at 10^-11m is (1.602x10^-19) / (4pix8.85x10^-12 x 10^-11)

V = 144V