Snell's Law and Light!!! 1. Use Snell's Law to show that a light ray which enters glass plane of wfinite width does not change direction when it exits the plate. 2. sin(theta in)/sin(theta refracted)= n2/n1 3. I know that if lamda in medium 1 does not equal lamda in medium 2, the direction of the wave changes. To show that the wave doesnt change directions we would need to show that lamba 1= lamda 2?