What Happens When a Laser Hits a Mirror Corner?

[IK0]

Question: If you were to theoretically shine a laser into the intersection of two mirrors, what would happen to the reflected beam? When I say 'theoretically' I mean that the beam would hit the corner perfectly.

I'm confused by this because the derivative of a sharp point on a graph is undefined, so it would seem that there would be no real reflective surface angle off of which the beam could reflect.

Also, treat the laser as if it has zero width (essentially, treat it as a line).

This is not a homework question - it's just something I thought up.
~IKnowN0thingEDIT: I thought that this would fit better over in the logic section, so I re-posted it there.

 

[Office_Shredder]

Let's simplify things. I have an infinitely thin laser beam. I shine it at the very edge of the mirror... does it reflect, or does it miss the mirror?

 

[mathman]

You can't make a laser beam of zero width. As a result each half would reflect off that mirror.

 

[IK0]

What if you made a single beam of electrons, and, (for sake of the question) they were to hit the corner perfectly? (The uncertainty principle aside...)

 

[johng23]

Well, for your mirror intersection to also be a perfect geometrical line, they each have to be atomically flat, in which case you don't really have an interface at all. So are you just asking what happens when you hit an atom with an electron head on? If things get to this length scale you need quantum mechanics for a reason.

 

[Dr Lots-o'watts]

I'm confused by this because the derivative of a sharp point...

Derivatives assume continuity. Matter can be considered continuous on a macroscopic scale, but on the molecular scale, we all know it's made of discrete atoms. At this point, you're talking about a single photon interacting with a single atom. This is where you need QM, and the answer will be a probability distribution for the outcome.

 

[IK0]

Oh I see. :)

Thanks for the help, this was really bugging me.