The spectral line for a given element in light received from a distant star is shifted towards longer wavelength by `0.024%`. Deduce the velocity of star in the line of sight.

Answer

`7.2 xx 10^(4)ms^(-1)`, moving away

Explanation

Here, `(Delta lambda)/(lambda) = (0.024)/(100) = 2.4 xx 10^(-4)`
`v = (Delta lambda)/(lambda)c = 2.4 xx 10^(-4) xx 3 xx 10^(8)`
`= 7.2 xx 10^(4) ms^(-1)`
As `lambda` increases, star must be moving away from earth