The speed of light in vacuum and in two different glasses is given in the table below :
Medium - Speed of light
Vacuum - 3.00 x 108 m/s
Flint glass - 1.86 x 108 m/s
Crown glass - 1.97 x 108 m/s
(a) Calculate the absolute refractive indexes of flint glass and crown glass.
(b) Calculate the relative refractive index for light going from crown glass to flint glass.
(a) nflint = \(\frac{speed \;of\;light\;in\;vacuum}{speed\;of\;light\;in\;flint\;glass}\)
= \(\frac{3 \times 10^8}{1.86 \times 10^8}\) = 1.61
ncrown = \(\frac{speed \;of\;light\;in\;vacuum}{speed\;of\;light\;in\;crown\;glass}\)
= \(\frac{3 \times 10^8}{1.97 \times 10^8}\) = 1.52
(b) crownnflint = \(\frac{speed\;of\;light\;in\;crown\;glass}{speed\;of\;light\;in\;flint\;glass}\)
= \(\frac{1.97 \times 10^8}{1.86 \times 10^8}\) = 1.059