A ray of light enters a glass block from air at an angle of incidence of 50 degrees. The angle of refraction is 30 degrees. What is the refractive index of the glass?

Question

What is the value of critical angle for this glass?

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Answer 1

n = sini/sinr =sin 50o/sin 30o =0.766/0.5 = 1.53.

n = sini/sinr =sin 50o/sin 30o =0.766/0.5 = 1.53
α = arcsin (n1/n2) = arcsin (1/1.53) = 40.81o.