Standing by the lake , Why does the water surface in the distance reflect strongly , And the reflection of the water near is weak （ You can see the bottom directly ）？
After reading Wiki's reflection equation today , Got it
https://zh.wikipedia.org/wiki/%E8%8F%B2%E6%B6%85%E8%80%B3%E6%96%B9%E7%A8%8B
![R_{s}=\left[{\frac {\sin(\theta _{t}-\theta _{i})}{\sin(\theta _{t}+\theta _{i})}}\right]^{2}=\left({\frac {n_{1}\cos \theta _{i}-n_{2}\cos \theta _{t}}{n_{1}\cos \theta _{i}+n_{2}\cos \theta _{t}}}\right)^{2}=\left[{\frac {n_{1}\cos \theta _{i}-n_{2}{\sqrt {1-\left({\frac {n_{1}}{n_{2}}}\sin \theta _{i}\right)^{2}}}}{n_{1}\cos \theta _{i}+n_{2}{\sqrt {1-\left({\frac {n_{1}}{n_{2}}}\sin \theta _{i}\right)^{2}}}}}\right]^{2}](/img/f0/1064b30adaba839dbb4bbb2f84d66b)
![R_{p}=\left[{\frac {\tan(\theta _{t}-\theta _{i})}{\tan(\theta _{t}+\theta _{i})}}\right]^{2}=\left({\frac {n_{1}\cos \theta _{t}-n_{2}\cos \theta _{i}}{n_{1}\cos \theta _{t}+n_{2}\cos \theta _{i}}}\right)^{2}=\left[{\frac {n_{1}{\sqrt {1-\left({\frac {n_{1}}{n_{2}}}\sin \theta _{i}\right)^{2}}}-n_{2}\cos \theta _{i}}{n_{1}{\sqrt {1-\left({\frac {n_{1}}{n_{2}}}\sin \theta _{i}\right)^{2}}}+n_{2}\cos \theta _{i}}}\right]^{2}](/img/6c/740183a719181386641baa02ca6be1)
Among them Rs or Rp Is the reflectivity under two polarizations , The higher the reflectivity , The stronger the light that enters the eye .
So analyze Rs, Think of it this way ： The difference between the incident angle and the refraction angle does not change much ,C = Angle of incidence A+ Reflection angle B,C As the incident angle increases , At an incident angle greater than 45 When the degree of ,C More and more 90 degree , At this time sin(B+C) It's a minus function , so Rs As the increasing function .
In this way, the angle between the incident light and the normal becomes larger and larger , The reflectivity is getting bigger and bigger , The reflected light becomes stronger and stronger .
In the same way Rp
