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COMEDK · Physics · 16. Waves and Sound

A galaxy moves with respect to the earth, so that sodium line of \(589.0 \mathrm{~nm}\) is observed at \(589.6 \mathrm{~nm}\). The speed of the galaxy is

  1. A \(300 \mathrm{kms}^{-1}\)
  2. B \(306 \mathrm{kms}^{-1}\)
  3. C \(400 \mathrm{kms}^{-1}\)
  4. D \(406 \mathrm{kms}^{-1}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(306 \mathrm{kms}^{-1}\)

Step-by-step Solution

Detailed explanation

Given, wavelength of sodium line, \[ \lambda=589.0 \mathrm{~nm}=5.89 \times 10^{-7} \mathrm{~m} \] Observed wavelength, \[ \lambda^{\prime}=589.6 \mathrm{~nm}=5.896 \times 10^{-7} \mathrm{~m} \] \(\therefore\) Change in wavelength,…