Under what conditions will light undergo total internal reflection?

Light undergoes total internal reflection when the angle of incidence is greater than the critical angle. The critical angle is the specific angle of incidence at which light, traveling from a denser medium to a less dense medium, will refract at an angle of 90 degrees, meaning it travels along the boundary.

When the angle of incidence exceeds this critical angle, all the light is reflected back into the denser medium rather than passing through the boundary. This phenomenon occurs because the refractive index of the denser medium is higher than that of the less dense medium. Under these conditions, instead of any portion of light being refracted into the less dense medium, it is entirely reflected back, showcasing the principles of optics related to light behavior at boundaries between different media.

Understanding the conditions for total internal reflection is fundamental in applications such as fiber optics, where controlling the pathway of light is crucial for efficient data transmission.