A narrow beam of alpha particles with kinetic energy T = 0.50 MeV falls normally on a golden foil whose mass thickness is pd = 1.5 mg/cm2. The beam intensity is I0 = 5.0 ∙ 105 particles per second. Find the number of alpha particles scattered by the foil during a time interval x = 30 min into the angular interval:
(a) 59-61°;
(b) Over θo ---- 60°