|Incident Angle (θ)||Angle from the normal to the surface.|
|Refraction Index (n)|
n = c / v = λair / λmedium
Refraction index of air: 1
|Refraction||For a ray travelling from one medium into another,|
n1 sin θ1 = n2 sin θ2
1 refers to incident side; 2 refers to refracting side
Sometimes when solving for θ1 or θ2, it cannot be defined.
|Critical Angle = θc|
The angle θc is where total internal reflection (TIR) occurs, whereby all light entering from medium1 to medium2 is reflected back into medium1.
n1 sin θc = n2 sin 90°