What Causes Total Internal Reflection?

[Reshma]

Can someone explain the phenomenon of total internal reflection?

 

[Doc Al]

Start here: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/totint.html

 

[Graeme Robinson]

Total internal reflection is a phenomenon that occurs when a ray of light strikes a boundary between two different mediums, such as air and water, at an angle greater than the critical angle. This critical angle is the angle at which the light ray is no longer able to pass through the boundary and instead is reflected back into the original medium.

This phenomenon is due to the difference in the speed of light in the two mediums. When light travels from a medium with a higher refractive index, such as water, to a medium with a lower refractive index, such as air, it slows down and changes direction. The critical angle is reached when the angle of incidence is such that the light ray would need to travel at a 90-degree angle to the boundary in order to pass through.

When this happens, the light ray is completely reflected back into the original medium, resulting in total internal reflection. This effect is commonly seen in nature, such as in the shimmering of a fish's scales or the sparkle of a diamond, and is also utilized in various technologies, including fiber optics and prisms.

Overall, total internal reflection is a fascinating phenomenon that occurs due to the properties of light and the differences in refractive index between two mediums. It plays a crucial role in both natural and technological processes, making it an important concept to understand in the study of light and optics.