The observed wavelength of light coming from a distant galaxy is found to be increased by 0.5% as compared with that coming from a terrestrial source. The galaxy is
Options

Question

The observed wavelength of light coming from a distant galaxy is found to be increased by 0.5% as compared with that coming from a terrestrial source. The galaxy is

G1 Physics · Accepted Answer

Step 1: For a small optical Doppler shift, Δλ/λ ≈ v/c. Step 2: 0.5% = 0.005, so v = 0.005c = 0.005×3×10⁸ = 1.5×10⁶ m s⁻¹. Increase in wavelength means recession. Final: D.