An X-ray photon scatters from a free electron with negligible initial kinetic energy at an angle of 121.2 degrees relative to the incident direction.

 
(Take the Compton wavelength of the electron to be 2.43 pm, and all other constants/conversions to three accepted sig digs.)
 
a)  If the scattered photon has a wavelength of 0.0690 nm, what is the wavelength of the incident photon?  (in nm)

b)  What is the kinetic energy of the recoil electron in electron volts?
 
(Because the Compton shift is so small, make sure to retain at least 4 sig digs in intermediate .)

c)  What is the speed of the recoil electron expressed as a percentage of the speed of light?
 
(Because the Compton shift is so small, make sure to retain at least 4 sig digs in intermediate calcs.)