This lesson explains how light changes direction when moving between mediums. Learn to calculate the refractive index using angles of incidence and refraction, and discover the critical angle and total internal reflection, including their conditions. We also establish the relationship between critical angle and refractive index for practical problem-solving.

OBJECTIVES:
1) Explain how the direction of light changes as it travels from one medium to another
2) Deduce the value of the refractive index of a given material from measurements of angles of incidence and refraction.
3) Explain the meanings of critical angle and total internal reflection, stating the conditions under which they occur. 4) Establish the relationship between critical angle and refractive index and apply it to the solution of simple problems.