Physics Research HW

Total internal reflection is a complete reflection of a ray of light within a medium such as water or glass from the suurounding surfaces back into the medium. This occurs when the angle of incidence is greater than a certain angle called the critical angle. Sometimes, when light is moving from a denser medium towards a less dense one, instead of being refracted, all of the light is reflected. This is also called total internal reflection.

The angle of incidence when the angle of refraction is 90°, and the ray changes from just refracting to total internal reflection, is called the critical angle. It is the greatest angle light can move at without any light being lost.

Total internal reflection allows light to be contained and guided along very thin fibres. Usually made of glass, these are called optical fibres. and they have many uses: fibre broadband internet sends computer information coded as pulses of light along underground optical fibres.

Total interal reflection allows the doctor to see an image of the inside of the body clearly, and help them diagnose diseases like cancer, or see what they are doing during keyhole surgery.