The living electron !Electricity and Magnetism Level 3
An alive electron was observing a photon with frequency f1 while it was coming to hit him!The photon has hit the electron and reflected in the opposite direction relative to the alive electron. The electron has seen the new reflected photon with a frequency f2. Assuming the the collision was elastic if observed from an inertial frame of reference.
The relation between f2 and f1 is: