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ove, , , , , why (=o), 3, Derive the re, , lation,, , , , , , , , , , , , bier ve: Ate, sm, 2, NuMERICALS, 1. A ray of light is incident on a 60° prism of glass of | 7. What should be the refracting angle of a prism of, refractive index 1.5 at an angle of 40°. Find the angle refractive index 1.5 so that a light ray incident on th, of emergence of the ray. Ans. 58.5’. prism at an angle of 50° suffers minimum ae, Meco and th : a, ; ns. ;, 2s The angle meen 60 hs i pera 8. The angle of a glass prism is 59.5°. The angle of, deviation is 39°. \ at is ie ce ractive index of the minimum deviation is 38.5°. Without using the va, material of the prism? (sin 49.5°= 0.76) Ans. 1.52. of refractive index of the glass, calculate the angle, 3. Calculate the refractive index of the material of an of incidence for a ray of light suffering minimum, equilateral prism for which the angle of minimum deviation. (ISC 2007), deviation is 60°. Ans. 1.732. Hint: i = (A + 8,) /2 Ans. 49°., 4. The refractive index of a prism of angle 60° is 1.62 for 9. A glass prism whose refracting angle is 72° and, sodium light. Find the angle of minimum deviation. refractive index 1.66 is kept in a liquid of refractive, (sin 54.1° = 0.81) : Ans. 48.2°. index 1.33, Calculate the angle of minimum deviation, , for the parallel beam passing through the prism., , _ 5. Calculate the angle of minimum deviation for a glass ‘, (Given : sin 36° = 0.5878, sin 47.2° = 0.7336), , prism of angle 60°, the refractive index of glass being, , 1,658. What is the corresponding angle of incidence? Ans. 22.4, sin 56° = 0.829, Ans. 52°, 56°. 10. A parallel beam of light is incident on a face of a 60, 6. A regular 60° glass prism has refractive index J2 for prism. By rotating the prism, the minimum angle of, ‘given wavelength. Calculate the angle of minimum deviation is measured to be 40°. Find the refracti, eviation 6,,. At what angle of incidence should a index of the prism material. If the prism is placed in, nochromatic light of this wavelength fall on the water (refractive index 1.33), then what would be th, , , , of the prism so as to get a minimum deviation? new minimum angle of deviation? —_ Ans. 1.53, 10!, in 30° = 1/ 2 and sin 45° = 1//2) 11, A ray of light incident at 50° on a 60° prism suffers, Ans. 8, = 30°, i= 45°. minimum deviation. Find the angle of minimum