The refractive index of a medium relative to air is 1.8. Calculate the critical angle for the medium to the nearest degree.

Answer Details

The critical angle is the angle of incidence in the medium for which the angle of refraction is 90 degrees (the refracted ray lies along the boundary). The critical angle is given by the formula `sin c = 1/n`, where `c` is the critical angle and `n` is the refractive index of the medium relative to air. Substituting `n = 1.8` into the formula, we get `sin c = 1/1.8 = 0.556`. Taking the inverse sine of both sides, we get `c = sin^{-1}(0.556)`. Evaluating this on a calculator, we get `c ≈ 34°`. Therefore, the critical angle for the medium is approximately 34 degrees. Answer is the correct answer.