Two hydrogen atoms collide head-on and end up with zero kinetic energy. Each atom then emits light with a wavelength of 121.6 nm (n= 2 to n= 1 transition). At what speed (ms ]) were the atoms moving before collision? A. 4.42 x 103 ms" ( B. 4.42 x104 ms-1 O C. 5.42 x104 ms"1 D. 6.42 x10# m5-1 O E. 3.42 x105 ms'1 A photon of initial energy 0.1 MeV undergoes Compton scattering at an angle of 60. Find the energy of the scattered photon. a. 8.24 x 104 ev () b. 8.21 x 10" ev O c. 9.24 x 104 ev O d. 9.11 x 10# ev