Fundamental interactions (Question 2 (15 Marks)) — UPSC Physics Optional CSE 2013 Paper II

In the following reactions indicate with an explanation, whether they proceed by strong, electromagnetic or weak interaction or they are forbidden:

(i) \pi^+ \longrightarrow \mu^+ + \nu

(ii) p \longrightarrow n + e^+ + \nu_e

(iii) p + \pi^- \longrightarrow K^+ + \Sigma^-