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Does total internal reflection happen with all types of waves, or just electromagnetic ones?
Antiphon said:It happens with any type of wave when the fields incident on the boundary can't launch a propagating wave in the other medium. This is usually due to different propagation speeds in the different media.
Ken G said:Yes, one way to think about that is that the wave that is incident on the boundary has a wavelength along its direction of motion, but that translates simply into a wavelength along the direction of the boundary. You just take the cosine of the angle to the normal, and divide the wavelength by that cosine, and you get the wavelength along the boundary. You can think of this is a surface wave propagating along the boundary, with that wavelength. Since the frequency of the wave is the same everywhere, you also know that frequency, so you can take the wavelength along the boundary, multiply it by that frequency, and you have the speed of propagation of that surface wave. Now you can ask if that surface wave can be connected to a propagating wave in the medium on the other side of the boundary, and the answer is no whenever the speed of the surface wave is slower than the speed of propagation in the medium on the other side of the surface. That's because the wave inside the medium can go no faster than the surface wave it is connected to-- by tilting the wave propagation direction away from that surface, you only slow down the speed of the wave, such that it matches into the speed of the surface wave.
Total internal reflection is a phenomenon that occurs when a light ray traveling through a medium reaches an interface with a less dense medium, and is completely reflected back into the original medium instead of being refracted.
Total internal reflection occurs due to the principle of Snell's law, which states that the angle of incidence of a light ray is equal to the angle of refraction at an interface between two materials. When the angle of incidence is greater than the critical angle, total internal reflection occurs.
Total internal reflection is used in various optical devices, such as prisms, binoculars, and fiber optics. It is also used in the design of reflective coatings for mirrors and lenses in cameras and telescopes.
The critical angle for total internal reflection depends on the refractive indices of the two materials at the interface, as well as the wavelength of the incident light. It also depends on the surface roughness and the angle of incidence.
No, total internal reflection can only occur in materials with different refractive indices, such as air and water, or air and glass. In materials with the same refractive index, such as air and air, total internal reflection cannot occur.