What is the correct equation for Snell's law?

• A. R = (Z2 - Z1)² / (Z2 + Z1)²
• B. Z = pc
• C. sin Øt = (C2/C1) x sin Ø1
• D. Fd = 2fvcos Ø/c

Answer: (C)

Snell's law, which describes the relationship between the angles of incidence and refraction when light passes from one medium to another, is accurately represented by the equation provided in the correct answer. In this equation, sin Øt represents the sine of the angle of refraction (the angle within the second medium), sin Ø1 is the sine of the angle of incidence (the angle within the first medium), and the ratio (C2/C1) corresponds to the ratio of the speeds of light in the two different media. This effectively illustrates how the change in speed of light results in a change in direction as light transitions between materials of different densities.

The formula demonstrates that the relationship is proportional, showing how much the angle of refraction will change relative to the angle of incidence based on the material properties. This is fundamental to understanding optical phenomena such as lens design, optical fibers, and various applications in physics and engineering involving wave propagation.

The other equations provided do not relate to Snell's law or the refraction of light. Instead, they address different physical principles, so they would not provide the correct foundation for understanding the behavior of light at interfaces between differing media.