1. Aim: How do we explain Snell’s Law?

2. Angle of Incidence and angle of refraction

3. Different angles of refraction for different media

4. Why do scuba divers wear face masks?

5. Snell’s Law
The index of refraction of the medium in which the light ray is incident multiplied by the sine of the angle of incidence is equal to the index of refraction of the medium in which the light rays refracts multiplied by the sine of the angle of refraction. n1sinθ1 = n2sinθ2

6. Derivation of Snell’s Law Using Huygen’s Principle

7. Solving Problems using Snell’s Law
The angle of incidence in both cases is 33 degrees. Calculate the angle of refraction in each circumstance.
n1sinθ1=n2sinθ2
1sin33°=1.33sinθ2
Θ2=24°
1sin33°=1.52sinθ2
Θ2=21 degrees

8. Sample Problems 3-4
The angle of incidence in each case is 42 degrees. Calculate the angle of refraction in each problem.
n1sinθ1=n2sinθ2
1.52sin42°=1.33sinθ2
Θ2 =50°
1.33sin42°=2.42sinθ2
Θ2 = 21.6°

9. The Layer Problem Find the angle at which the light enters the air.
42 degrees