The spectral line for a given element in the light received from a distant star is shifted towards longer wavelength side by `0.025%`. Calculate the velocity of star in the line of sight.

Explanation

Here, `(Delta lambda)/(lambda) = 0.025% = (0.025)/(100) = 2.5 xx 1-^(-4)`
As `(v_(s))/(c ) = (Delta lambda)/(lambda) :. v_(s) = (Delta lambda)/(lambda) xx c = 2.5 xx 10^(-4) xx 3 10^(8) = 7.5 xx 10^(4) ms^(-1)`
As shift is towards longer wavelength side, the star is moving away.