How and why does a mirror reflect light?

[pivoxa15]

A fundalmental, atomic but also basic (2nd year Uni level maths and physics or less) explanation would be good.

 

[ZapperZ]

Try reading this thread:

https://www.physicsforums.com/showthread.php?t=116678

Zz.

 

[astrokreng]

A mirror reflects light through the process of reflection, which is a fundamental property of light. Light is made up of tiny particles called photons, which travel in straight lines until they hit an object.

When light hits a smooth and flat surface, like a mirror, the photons bounce off at the same angle at which they hit the surface. This is known as the law of reflection, which states that the angle of incidence (the angle at which the light hits the surface) is equal to the angle of reflection (the angle at which the light bounces off the surface).

The reason for this is because smooth and flat surfaces, like mirrors, have atoms that are arranged in a very specific and uniform manner. When a photon hits the surface, it interacts with the electrons in the atoms, causing them to vibrate. These vibrating electrons then emit a new photon, which is the reflected light.

The reason why the angle of incidence is equal to the angle of reflection is because of the conservation of energy and momentum. This law states that the total energy and momentum of a system must remain constant. In the case of reflection, the incoming photon has a certain amount of energy and momentum, and when it is reflected, it must maintain that same amount of energy and momentum. This is why the angle of incidence and reflection must be equal.

In summary, a mirror reflects light because of the law of reflection and the properties of light and atoms. The smooth and flat surface of a mirror allows photons to bounce off at the same angle at which they hit, due to the interactions between the photons and the vibrating electrons in the atoms. This process follows the laws of conservation of energy and momentum, resulting in the familiar reflection we see in mirrors.