Answer :
The phenomenon that occurs here is known as the snell's window, and the cone angle is 98 degrees.
To calculate the cone angle,
The cone angle is equal to two times the critical angle which is say, Ф
To calculate the critical angle Ф take the equation sinФ = n1÷n2 where
n1 is the refractive index of air, and n2 is the refractive index of water.
The refractive index of air, n1 = 1,
The refractive index of water, n2 = 1.33,
Substituting these values in the equation sinФ = n1÷n2, the equation becomes
sinФ = 1÷1.33
solving for Ф
Ф = [tex]sin^{-1}[/tex](1÷1.33)
Ф = 49°
Cone angle = 2×Ф
Cone angle = 2×49
Cone angle = 98°.
The phenomenon taking place here is known as snell's window. In this phenomenon, the person under the water sees everything above the surface through a cone of light whose width is about 96°-98°. Whatever is outside this cone appears dark to the person who is under the water. This is caused due to the refraction of light in different mediums.
Learn more about snell's window at
https://brainly.com/question/10112549?referrer=searchResults
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