When an electron emits a photon, which direction does it go?

Question

Does it go in one direction (like a particle), or does it emit (like a ripple) in all directions simultaneously?

If emitted in one direction (like particle), how is it that a mirror is capable of reflects these photons in exactly the same direction that they came from? Where aren't they bounced in all random directions?

Answer 1

Even though they have no mass, photons have momentum, which must be conserved. So a photon being re-emitted will either be passed along with its original momentum for a transparent medium, or bounced back like a ball off a wall for a reflective medium. Photons due to energetic processes in the material (heat, for example) are emitted as spherical wavefronts, constrained by directionality imposed by the geometry of the emitter. So a photon emitted from a flat surface will have a wavefront that covers a hemisphere. An individual photon will interact with matter at only a single point, of course, but the wavefront shows the probability distribution of that interaction.

Answer 2

This is sort of a quantum mechanical questoin. However its easier to approximate classically. In the clasical model the photon is emitted in one direction and bounces off a mirror as a ball bounces of a wall.
Quantum mechanicaly speaking the photon could have been emitted in any direction and until you observe it, it could be traveling in any direction. However once you observe it hitting the mirror then it has been established that it did indeed travel twards the mirror.

Answer 3

Light seems to propegate in all directions equally unless it is amplified and emitted (such as in a LASER) in a coheisve manner.

Answer 4

it behaves like a particle. i believe the direction is random.

Answer 5

The direction is random and is impossible to predict.