Question

5. Unpolarized light from the Sun reflects from the surface of water (n = 1.33). At what angle of incidence (relative to the normal) does the reflected light become completely polarized? Draw this scenario and indicate the direction of polarization of the reflected ray (remember you can use a O, or an® to represent polarization perpendicular to the page). 6. Red laser light enters a fiber optic cable (left edge) at an angle @(measured from the normal) and propagates down the fiber. The fiber's refractive index is 1.30, and it is surrounded by air (n = 1). Draw in your normals, and calculate the maximum value of e, for total internal reflection to occur along the length of the fiber optic cable.

Answer 1

Solution: 5 At Bremester Angle incident light does the complety It we take Oo as Brawster unpolarised polarised reflected angle, then light. tanda = 2 - here na = 1.33 ni = 1 tem do = 1.33 " OB & tour' (1.33) » Oo = 53.06 / So which the angle from normal is QB = 53.06 at all the reflected light becomes polarised. Reflected light incident light Cunpolarised) 7 (polarised) n = 1 12= 1. 33 a Refracted light C slightly bolcerised)

n =1 M = 1.30 02_ Here we have to calculate the value of o, for which there will be Total internal reflection So by Snell's law - ni sina = masina ci and when Total internal reflection happens = along the length of fiber then Oz should be a critical angle, so sinds = mind sin d = 1 1.30 O3 = sint line) ☆ O3 = 50.285° Then by Geometry O2 = 90 - 03 O = 90'- 50.285- O2 39.7150 Now, from ean ci Sin Q1 = masinos

sino = 1,30 Sén 39.715 7 GOOOOOO 0 O = = sånt C0.83) 56,0990 So for Total 56.099. internal reflection or should be