Physics 2000 JAMB Past Questions - Question 16: Total internal reflection occurs when light moves from

Correct Answer

C

Explanation

Total internal reflection occurs when light moves from a medium with a higher refractive index to a medium with a lower refractive index at an angle of incidence greater than the critical angle. The critical angle is the angle of incidence at which light, instead of refracting into the second medium, is reflected back into the first medium. This phenomenon is a result of Snell's Law, which describes how light is refracted at the boundary between two media with different refractive indices.

Total internal reflection is commonly observed at the interface between a denser medium (higher refractive index) like glass or water and a less dense medium (lower refractive index) like air. When the angle of incidence exceeds the critical angle, all of the light is reflected back into the denser medium, and none of it is transmitted into the less dense medium.

This phenomenon is exploited in various optical applications, including fiber optics, prisms, and optical communications, to ensure that light is guided and reflected within the medium with a higher refractive index, allowing for efficient transmission and minimal loss of light.