A star is moving towards the earth with a speed of `9 xx 10^(6) m//s`. If the wavelength of a particular spectral line emitted by star is `600 nm`, find the apparent wavelength.

Answer

`582 nm`

Explanation

Here, `v = 9 xx 10^(6)m//s, lambda = 600 nm, lambda' = ?`
`Delta lambda = -(v)/( c )lambda = -(9 xx 10^(6))/(3 xx 10^(8)) xx 600 = - 18 nm`
`:. lambda' = lambda + Delta lambda = 600 - 18 = 582 nm`