What is the boundary behaviour of light waves?

The boundary behaviour of light waves refers to their reflection, refraction, or transmission when they encounter a boundary.

When light waves encounter a boundary between two different media, they can either be reflected, refracted, or transmitted. This behaviour is governed by the laws of reflection and refraction, which are fundamental concepts in the study of optics.

Reflection occurs when light waves bounce off a boundary, changing their direction but not their speed or frequency. The law of reflection states that the angle of incidence (the angle between the incoming light wave and the normal to the boundary) is equal to the angle of reflection (the angle between the reflected wave and the normal). This is why, for example, we can see our reflection in a mirror - the light waves from our body hit the mirror and are reflected back to our eyes.

Refraction, on the other hand, involves a change in the direction of light waves as they pass from one medium to another. This is due to a change in the speed of light in different media, which causes the light waves to bend. The law of refraction, also known as Snell's law, describes the relationship between the angles of incidence and refraction and the indices of refraction of the two media. This is why, for example, a straw appears to bend when it is placed in a glass of water - the light waves from the straw are refracted as they pass from the water to the air.

Transmission is when light waves pass through a boundary without being reflected or refracted. This usually happens when the two media have the same or very similar indices of refraction. For example, light waves can be transmitted through a pane of glass, allowing us to see through it.

In summary, the boundary behaviour of light waves involves their reflection, refraction, or transmission when they encounter a boundary between two different media. This behaviour is governed by the laws of reflection and refraction, which are key concepts in the study of optics.