[UPSC CSE 1997] Particle Physics (Q315, 20M)

Mention the conservation law violated in the following elementary particle reactions:

(i) \mu^- \rightarrow e^- + u_o

(ii) n \rightarrow p + e^-

(iii) k \rightarrow \pi^o + \pi^o

(iv) e^- + e^- \rightarrow \gamma