Monochromatic light of wavelength 589 nm is incident from air on a water surface. What are the wavelength, frequency and speed of (a) reflected, and (b) refracted light? Refractive index of water is 1.33.

Explanation

For reflected ray, (in air)
Wavelength,
`lamda=589nm" "("":.` Medium remains same)
Frequency,
`f=(c)/(lamda)=(3xx10^(8))/(589xx10^(-9))=5.093xx10^(14)Hsz`
Speed,
`c=3xx10^(8)m//s`
(b) For refracted ray, (in water)
Wavelength,
`lamda.=(lamda)/(n)=(589)/(1.33)=442.86nm`
Frequency,
`f=5.093xx10^(14)Hz`
( `:.` It does not change with the change in medium)
Speed,
`v=(c)/(n)" "("":.n=(c)/(v))`
`=(3xx10^(8))/(1.33)`
`:.v=2.256xx10^(8)m//s`