Electrons got ejected out as if they were ping pong balls by the light particle (photon). Electrons were not moving initially. Then, it was moving later because of the light.

1. What is the momentum of the electron initially
2. Does the electron have momentum after being hit by the light particle? Hint: Is it moving after being hit?
3. What can you infer about light particles and momentum?Hint: Where is the electron getting its velocity from?