Question

Light is normally incident on one face of a 23 ^o flint-glass prism. Calculate the angular separation (deg) of red light (λ = 650.0n m) and violet light (λ = 450.0n m) emerging from the back face. Use n_red = 1.644 and n_violet = 1.675. (See the figure. Note that the angle of the prism may be different in your problem.)

8. (Violet) - (Red) Bodeg Red 30deg Violet Figure 24.33

Answer 1

Oi Medium I ny Medium 2 When a light beam incident at the interface of two different medium then refraction occurs. Snell's law of refraction states that Sino; ng Sinos Where light beam Brom medium 1 of refractive index (v.) n, incident at an angle Oi at the interface and gets refreacted to the medium a of pefractive index Ng . Ons is the angle of refraction . Ops can also be called as denoted as of . angle Top transmission and

Angle of prisno Back face of prism (90-0) "Ot/Red) 904-19036) I Of(violet) – OL(Red) e Red Oz/violet) Front Violet face of prism

of the Blint glass ng n flint Nair Refractive index of the flint glass ie refractive index with respect to aire is glass ng is a Bunction of Wavelength. Fore Red light refractive index of the priom for violet light refractive index of the prism Nred 1.644 Nviolet = 1.675 Angle of the prism is 25° So the angle of incidance at the back surface Applying Oi=23° Snell's law for reed Sinoi Nair Sin (Och med light ( vtint glas) ned =) Sin 23° sin (Ot) med Sin 1.644 (Ot) red -1 1.644X Sin 23° o 39.9681 ~ 39.97 0 Snello law for Violet light naire Nflint Sin ; Sin (Olviolet Sin 23 Sin (92) violet gles) violet 1.675 (oel violet Sin 1:675 x Sin234)

o (OE) violet 40.87981 ã 40.88 0 The angular separation of red light and violet light (emerginea from the back face of prism) is (O2) violet - (Oc) red 40.88° - 39.97° 0.91° = the light no Sin on ** At the front face of prism incident normally ie angle of incident O;=0. Now from snell's Law Sino° ти Sinop=0 = Op = 0 ise for normal incidance, the angle of refraction is zerco i,e there will be no deviation of retracted beam. no deviation shown in the front face of prism. Hence there is