入射角和折角之间的差异

Key Difference – Angle of Incidence vs Angle of Refraction

Thekey differencebetween the angle of incidence and angle of refraction is两个角度的顺序顺序通过波在介质界面上制成。

Refraction is a property of waves. A wave can have differentvelocitiesfor different mediums. The change of velocity at a boundary of a medium causes a wave to refract. This article is particularly focused in light rays, for the sake of simplicity.

Definition of Angle of Incidence and Angle of Refraction

Angle of incidenceis the angle between the normal at the interface and incident ray.

Angle of refraction定义为界面处的正常角度之间的角度refracted ray. Angles can be measured by any unit, but here, degrees are used. Let us first have a glance atlaws of refraction.

1. Incident ray, refracted ray and the normal at the interface lie in the same plane.
2. 界面处的入射角（i）与折射角（r）的正弦（i）保持恒定关系。该常数称为第二介质的折射率。

请记住光的可逆性。如果我们只是通过将当前端视为启动和当前开始作为末端来逆转光线的方向，则灯光将追踪相同的路径。

Formation of Angle of Incidence and Angle of Refraction

The difference between incident and refracted ray depends on the fact whether the light ray comes to the interface or leaves the interface. Picture a light ray as a stream ofphotons.The stream ofparticles击中与正常的一定角度的界面，然后沉入另一个介质中，基本上与正常人形成不同的角度。

Theangle of incidencecan be varied manually since it is independent of the medium. But theangle of refractionis defined by the refractive indices of the media. More the difference between refractive indices, more the difference between angles.

相对于界面相对于界面的入射角和折射角的位置

If a light ray goes from medium1 to medium2, the angle of incidence lies in the medium1 and the angle of refraction lies in the medium2 and vice versa for interchanging of the mediums.

两个角度都是在介质界面处的正常角度制成的。根据相对折射率的不同，折射光线的角度可能大于或小于入射光射线。

Values of Angle of Incidence and Angle of Refraction

Refracting from a rarer to denser medium

Any value between 0 to 90 degrees can be assigned as the angle of incidence, but the refracted ray cannot be taken any value if the light ray comes from the rarer medium. For the entire range of the incident angle, the angle of refraction reaches a maximum value which is exactly the same as the critical angle described next.

Refracting from a denser to rarer medium

The above is not valid for a situation where the light ray comes from a denser medium. When we increase the incident angle gradually, we shall see the angle of refraction also increases rapidly until a certain value of the incident angle is reached. At this critical angle(c) of the incident ray, refracted light ray achieves its maximum value, 90 degrees (refracted ray goes along the interface) and vanishes for a moment. If we try to increase the incident angle further, there we shall see a sudden appearance of a reflected ray in the denser medium, making the same angle according to the laws of reflection. The incident angle at this point is called the critical angle, and there will be no more refraction.

As a summary, one could see, though categorized differently, both these phenomena are just a result of the reversibility of light.

Key difference

The key difference between the angle of incidence and angle of refraction is the sequential order of the two angles, made at a media interface by a wave.

Image Courtesy:

“Snells law2” by Oleg Alexandrov — I just tweaked the original – Rotated and tweaked version of en:Image:Snells law.svg, same license.(Public Domain)viaCommons

“RefractionReflextion” by Josell7 – Own work.(CC BY-SA 3.0)viaCommons