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a) A ray of light 480nm wavelength in air (n=1) makes an angleof incidence, 30.0

ID: 1757132 • Letter: A

Question

a) A ray of light 480nm wavelength in air (n=1) makes an angleof incidence, 30.0 degrees, as it enters clear ice (n=1.309), Findi) the angle of refraction, ii) the speed of light in the ice andiii) thewavelength of light in ice. (speed of light in air=3x10^8) b) The critical angle for total internal reflection at diamondair interface in 41 Do. What is the speed of light in thediamond? a) A ray of light 480nm wavelength in air (n=1) makes an angleof incidence, 30.0 degrees, as it enters clear ice (n=1.309), Findi) the angle of refraction, ii) the speed of light in the ice andiii) thewavelength of light in ice. (speed of light in air=3x10^8) b) The critical angle for total internal reflection at diamondair interface in 41 Do. What is the speed of light in thediamond?

Explanation / Answer

wavelength = 480 * 10 ^ -9 m incident angle i = 30 degrees index of refraction of ice n = 1.309 (i). from snell's law   sin i / sin r = n                                      sin r = sin i / n                                             = 0.3819    angle of refraction r = 22.45 degrees (ii) .speed of light in ice v = c / n                                       = ( 3 * 10 ^ 8 ) / 1.309                                       = 2.291 * 10 ^ 8 m / s ( iii) . wavelength of light in ice '= / n                                                    = 366.69 nm (b) . critical angle C = 41 degrees we know sin C = 1/ n ' from this index of refraction of diamond n ' = 1 / sinC                                                                 = 1.5242 So, speed of light in diamond v ' = c / n '                                                  = ( 3 * 10 ^ 8 m / s ) / 1.5242                                                  = 1.968 * 10 ^ 8 m / s