3N3

is unpredictable

Physics.
Teacher-in-charge: Mr chio
Students: Adlin, Diyanah, Elisa, Grace, Jermaine, Jingsheng, Pauline, Qianwei, Saiful, Tabatha, Vinis, Wende, Zongxian,

The Critical Angle

In our introduction to TIR, we used the example of light traveling through water towards the boundary with a less dense material such as air. When the angle of incidence in water reaches a certain critical value, the refracted ray lies along the boundary, having an angle of refraction of 90-degrees. This angle of incidence is known as the critical angle; it is the largest angle of incidence for which refraction can still occur. For any angle of incidence greater than the critical angle, light will undergo total internal reflection.

So the critical angle is defined as the angle of incidence which provides an angle of refraction of 90-degrees. Make particular note that the critical angle is an angle of incidence value. For the water-air boundary, the critical angle is 48.6-degrees. For the crown glass-water boundary, the critical angle is 61.0-degrees. The actual value of the critical angle is dependent upon the combination of materials present on each side of the boundary.

adapted from http://www.physicsclassroom.com/class/refrn/u14l3c.cfm

JERMAINE,