Electrons accelerated to an energy of 50GeV have a de Broglie wavelength small enough for them to

Question:

Electrons accelerated to an energy of 50GeV have a de Broglie wavelength λ small enough for them to probe the structure within a target nucleus by scattering from the structure. Assume that the energy is so large that the extreme relativistic relation p = E/c between momentum magnitude p and energy E applies. (In this extreme situation, the kinetic energy of an electron is much greater than its rest energy.)
(a) What is λ?
(b) If the target nucleus has radius R = 5.0 fm, what is the ratio R/λ?