Question

4. A ray of light in water is travelling parallel to the base of a glass tank. The tank has a 50° angle with the horizon. The index of light in air is 1.00, in water is 1.33, and in glass is 1.50. gloss w Light រប° Determine the angle of the ray reflected off of the water glass interface. Determine the angle of refraction at the water glass interface. Determine the angle of refraction at the glass air interface. In which of the three materials (water, glass, air) does the light travel the fastest? In which of the three materials (water, glass, air) does the light travel the slowest?

Answer 1

Z P { 500 . 50 by drawing the normal line ON we get at point o, the angle of incidence is 90-50°- 40°

bays that so, the pays that would be partially reflected, have angle of reflection Reflections a with the Normal ce ON so angle of reflection 40" w is is the angle of refraction, then by Snell's law ng Sin sing nw where ng - nefractive inden of glass -1.5 e the nefractive inden of water nw=1.33 sings a ni sini 91 ng e, a. Da ng we have is 409 1.33 sinto pa = sint L 1.5 inae. a

- 8 = 34.74592663" p = 34.75 appoon) Now, if we draw perpendicular ( normal live mp) at the grass-win interface at point in, since ON. II.mp on hence the angle of incidence glass-air interface is also the 8. if, il is the through air snell's law, agnle of Refraction then again by sini 1.5 sing 1.5 sing 7 sini ₃ is singissing? putting, = 34.74592663

we get, i= sinthiis sin (34.7459266 y ✓ = 58.74951959° Cappoon) 58.75° 2 the TA we know that if e is speed of light in empty space, e if we have a medium with absolute nefractive inden u , then, speed of light in that medium will be c'a uk we have, cain) Marl " w=1.33 (water) & Mg=1.5 (glase) > so ^ 33 it is water) (sreed at grass) cit (speed at air)> (speed

so, travel the fastest The light through ain &, The light travel the slowest through the glass .