Q.1 A charged T-meson of rest mass 139.3 MeV/c2 decays at rest into a muon particle of rest mass 105.47 MeV/c2 and a neutrino of zero rest mass. Find the kinetic energies of the muon and neutrino. Q.2 A particle of rest mass m. moves at a velocity u and collides with a stationary particle of rest mass M.. If the particles stick together after the collision, find the speed of the composite mass. Q.3 If a photon of energy E1 collides at an angle 0 with another photon of energy E2, prove that the threshold energy for first photon, (E1)th; required for the formation of a pair of particles of mass m is given by 2m?c4 (E1)th E2(1 cos 0)