Of light and mirrors

Light is an electromagnetic wave that exhibits both wave and matter-like properties yes? I was wondering what happens to light when it reflects off a mirror.

If a tennis ball is thrown at a wall, the moment of contact between the ball and the wall is very brief, so the deceleration rate is very, very high right? Say the ball was travelling 20ms^-1 then bounces back at around -19ms^-1, making a difference of 39ms^-1. The length of time the ball contacts the wall is around 0.02s (for the sake of example). Then the deceleration would be 1950ms^-2. There is a point in time where the ball is simply stationary.

Light travels at around 299,792,458ms^-1. The moment of 'contact' is near negligible, most likely in the picoseconds. Even so, there must be a measure of deceleration for light whether it is a particle (matter) or wave (radiation). If this is the case, then what kind of properties would light have at the inevitable point in time of 0 velocity?

If I have it all wrong and there is a separate set of physical laws governing EM radiation, what is it?

diazona
Homework Helper
In fact there is a separate set of physical laws governing EM radiation:
$$\vec{\nabla}\cdot\vec{D} = \rho_f$$
$$\vec{\nabla}\cdot\vec{B} = 0$$
$$\vec{\nabla}\times\vec{E} = -\frac{\partial\vec{B}}{\partial t}$$
$$\vec{\nabla}\times\vec{H} = \frac{\partial\vec{D}}{\partial t} + \vec{J}_f$$
The process of solving those equations to figure out what happens at a reflecting surface is kind of long and involved, but you do find that EM waves are reflected without undergoing any change in speed. There's no point at which the light is not traveling at 299792458 m/s (which is an exact value, by the way). That's consistent with relativity, which says that anything that ever travels at the speed of light will always travel at the speed of light.

Andy Resnick