The spectral line for a given element in light received from a distant star is shifted towards the longer wavelength by 0.032%. Deduce the velocity of star in the line of sight.
Here, ∆λ/λ = 0.032/100
v = ?
Since, the wavelength of light from a star is shifting towards longer wavelength side, then ∆λ is positive, hence star is moving away from the earth, i.e. v is negative.
c = -∆λ/λ c = -0.032/100 x 3 x ${{10}^{8}}$
= 9.6 x ${{10}^{4}}$ m/s