The earth is moving towards a fixed star with a velocity of 30   km s - 1 . An observer on the earth observes a shift of 0.58   Å in the wavelength of light coming from the star. What is the actual wavelength of light (in μ m ) emitted by the star?

Step-by-step solution

Using, Δ λ = v c λ Here v = 30   km s - 1 = 3 × 10 4   m s - 1 c = 3 × 10 8   m s - 1 Δ λ = 0.58 × 10 - 10 m ∴   λ = c v Δ λ = 3 × 10 8 3 × 10 4 × 0.58 × 10 - 10   m = 0.58 × 10 - 6   m = 0.58   μ m