A star is moving away from earth and shift in spectral line of wavelength 5700 Å is 1.90 Å. Velocity of the star is
Answer & explanation
Correct answer: option 4
$Δλ=\frac{v}{c}λ$ $∴\frac{cΔλ}{λ}$
or $v=\frac{3×10^8×1.9×10^{-10}}{5700×10^{-10}}=100\,km\,s^{-1}$