Question

3. At what angle of incidence in air would a ray of light have to enter crown glass to have a refraction angle of 26 degrees? 4. The speed of light in medium M is 2.69x10^9 m/s. What is the critical angle in M (relative to air)?

Answer 1

cies Answer 3. Alc Snell's law, u, sini = usinr, where u, Refractive index of l, =1.0 id Augle of incidence 260 M, Refractive index of crown glass U₂=1.5 8- Augle of refraction -)1.0 sini = 1.5 Sin 26° i 1.5 =) sini = Sin 26° = 1.5 x 0.44 -0.66 a) i . Sin '0.66 - 41°

4 . naj where n-tindex of refraction of na 3.00x10 m/s light in vaccum 2.69 X 109 mis v + Velocity of light in medium n=1.12X10-' : 0.112 c+Velocity Sinea 1 where on Critical angle nindex of refraction ocasint "ห O casin - Sin '18.92) This is not possible because domain of sin's is tij Hence Oc is not possible in this medium. 0.112

3. Angle of incidence is 41 degrees.

4. If the answer is different then must be some mistake in value of speed of light in medium, otherwise any value for critical angle is not possible.