Which principle explains the bending of light in a prism?

• A. Refraction Law
• B. Newton's Law
• C. Snell's Law
• D. Reflection Law

Answer: (C)

The bending of light in a prism is best explained by Snell's Law, which describes how light changes direction when it passes from one medium to another with a different refractive index. Snell's Law quantitatively relates the angles of incidence and refraction to the indices of refraction of the two media involved.

When light enters a prism, it travels from air (a less dense medium) into glass (a denser medium). According to Snell's Law, the light ray will bend towards the normal line at the point of entry due to the change in speed as it moves from air to a denser medium. As the light exits the prism back into air, it bends away from the normal. This bending of light at both interfaces of the prism leads to the dispersion of light into its constituent colors, creating a spectrum.

This principle is crucial in understanding various phenomena involving lenses, optical fibers, and numerous applications in optics and engineering. The connection established by Snell's Law provides not just a description, but also a predictable means to calculate how light will behave as it passes through different materials, which is fundamental in the study of optical devices.