The wavelength of sodium light in air is 589 nm. (a) Find its frquency in air. (b) Find its wavelength in water (refactive index = 1.33). (c ) find its frequency in water : (d) Find its speed in water.

Explanation

Here, `lamda_0 = 589 nm = 589 xx 10^-9 m, mu = 1.33`
`lamda = (lamda_0)/(mu) = (589)/(1.33) = 442.85 nm`
`v = v_0 = (c)/(lamda_0) =(3 xx 10^8)/(589 xx 10^-9) = 5.09 xx 10^14 Hz`
`v = (c)/(mu) = (3 xx 10^8)/(1.33) m//s = 2.25 xx 10^8 m//s`.