中學物理光的問題?

1. When light passes from a dense medium to a less dense one, the critical angle (臨界角) is the incident angle (入射角) at which the refracted angle (折射角) equals to 90 degrees.
For incident angle greater than the critical angle, total internal reflection (全內反射) will occur.

2. A medium is a non-conducting substance permitting electromagnetic waves (電磁波) (e.g. light) to pass through.

3. Refractive index of a substance can be obtained by measuring the incident angle and refracted angle, and then calculated by using Snell's Law.

It can also be found theoretically by measurig the permeability and permittivity of the substance.


2014-06-01 19:26:07 補充：
Your suppl question:
"critical"(臨界) means the point at which, if exceeded, leads to some change in the physical phenomenon. In your problem, the physical phenomenon involved is the change from refraction to reflection.