Problem 8: Calculate the electric potential at the surface of a silver nucleus having radius 3.4 × 10^-14 m. The atomic number of silver is 47 and charge on proton is 1.6 × 10^-19C.

Quite easy! Do it yourself.
Make your strategy as the nucleus acts as a point charge. Atomic number means the number of proton in the nucleus; therefore, total charge on the nucleus is 47 times the charge on a single proton. Distance is equal to the radius of the nucleus. Use formula, V = K q/r.