When measured carefully, the refractive index for glass is different for different colors of light. For red, it is 1.51 and for blue, it is 1.52. What is the speed of both colors in glass?

1 Answer
Dec 27, 2017

See the explanation below

Explanation:

The refractive index of glass is

#n_g="speed of light in vacuum"/"speed of light in glass"#

The speed of light in vacuum is #c=3xx10^8ms^-1#

Therefore,

#n_(red)=1.51=(3*10^8)/v_(red)#

The speed of red light is

#v_(red)=(3*10^8)/1.51=1.987*10^8ms^-1#

Therefore,

#n_(blue)=1.52=(3*10^8)/v_(red)#

The speed of blue light is

#v_(blue)=(3*10^8)/1.52=1.974*10^8ms^-1#