Answer:
78.35°
Explanation:
THIS IS THE COMPLETE QUESTION BELOW;
A layer of ethyl alcohol (n = 1.361) is on top of water (n = 1.333). To the nearest degree, at what angle relative to the normal to the interface of the two liquids is light totally reflected?
From Snell's Law,
(ni)/(nr) = Sin (θr) / Sin (θi)
Where
θi = Angle of Incidence
θr = Angle of refraction
ni = Refractive index given for ethyl alcohol
nr = Refractive index of medium from which light is refracted
ni = 1.361
nr = 1.333
, θr = 90° ( Critical Angle is reffered to as Angle of Incidence at refracted angle of 90°) (θi = θc)
(ni)/(nr) = Sin (θr) / Sin (θi)
1.361/ 1.333 = Sin (90°)/ Sin( θc)
1.021= 0.894/ Sin( θc)
Sin( θc)= (0.9794
θc = Sin⁻¹ 0.9794)
θc = 78.35°
