Answer:
73.13°
Explanation:
According to snell's law,
n1sinθi = n2sinθr
n1/n2 = sinθr/sinθi
Critical angle is the angle of incidence at the denser medium when the angle of incidence at the less dense medium is 90°
This means i=C and r = 90°
The Snell's law formula will become
n1/n2 = sinC/sin90°
n2/n1 = 1/sinC
Where n1 is the refractive index of the less dense medium = 1.473
n2 is the refractive index of the denser medium = 1.540
Substituting the values in the formula,
1.540/1.473 = 1/sinC
1.045 = 1/sinC
SinC = 1/1.045
SinC = 0.957
C = sin^-1(0.957)
C = 73.13°