Question

Monochromatic radiation enters an equilateral triangular prism (all sides including the apex angle are 60°) at an angle of refraction that is parallel to the base of the prism. If the refractive index of the prism is 1.45 to this wavelength of radiation, calculate the angle of incidence and the angle at which this radiation exist the prism.

Answer 1

Here we apply concept of refraction through prism and Smell's Law of refraction.

Refractive index Up = 1.45 so Mais = air 160 As incident ray Priem is parallel to priem t goo . O; = 600 0;= incident angle LO; 2381 Angle of incidence de 300 I How Of de refraction angle due to refraction hat face (left tuce] I Vein Snell's law Mair Simo; = Mp Sinor (1) Sin 30° = 0.45) Sin or > Or = 20.20 from A ABC LABC = 9o-Oy RA 2 BAC = C6° CACB = 180° - LBAC - LABC = 180° - [60° +90 - Os] = 30° +20.20 = 50.20

z = incident angle on right face so l = g8o _ LACB = 90 - 50.20 = 39.80 How second at right refraction face izt Reair Snell's law Prilim Up Sin iz= Mair sine = (1.45 Sin 39.8° = ) Sine e = 68.10 at 68.1 as the emergent angle or 90°-68.1 = 2190 with prism.