Question

Snell's law describes the relationship between the angle a light ray makes as it leaves a surface, the angle it makes incident on the surface, and the indices of refraction on both sides of the surface. If light incident in air at angle of 30 degrees from the normal onto glass with an index of refraction of 1.5 --Pick those answers that applya) Inside the material, the light leaving the surface is closer to the surface, makes a bigger angle with the normal, than the entering light makes in air.b) The light inside the glass is closer to the normal, makes a bigger angle with the surface, than the incident lightc) There is light reflected back into the air from the surfaced) The angle is too steep for light to refract and it is all reflected.

Answer 1

b) and c)

Step-by-step explanation:

• Snell's law states that there exists a fixed relationship between the sine of the angle that makes with the normal an incident ray on the separation surface of two transparent media, the sine of the angle that is refracted off the surface, and the indexes of refraction of both media, as follows:

`(sin_(\theta i))/(sin_(\theta r) ) =(n_(2) )/(n_(1) ) (1)`

• Givens:
• θi = 30º
• n₁ = 1 (air)
• n₂= 1.5 (glass)
• Since sin 30º = 0.5, we can solve for sin r, as follows:
• 
  `sin \theta r = (sin_(\theta i))/(n_(2)) = (0.5)/(1.5) = 0.333 (2)`
• As the sin r is lower than sin i, this implies that the angle that makes with the normal is lower than i, which means that it makes a bigger angle with the surface, as stated by b).
• Also there is some light that is reflected by the surface, making an angle with the normal equal to the incident ray, as stated by c).
• So, b) and c) are the right choices.