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AP EAMCET · PHYSICS · Wave Optics

For an observer on the earth, if a spectral line of wavelength \(6600 Å\) emitted by a star is found to be red shifted by \(22 Å\), then the star is

  1. A receding away from earth with a speed of \(9 \times 10^5 \mathrm{~m} \mathrm{~s}^{-1}\)
  2. B receding away from earth with a speed of \(10 \times 10^5 \mathrm{~m} \mathrm{~s}^{-1}\)
  3. C moving towards earth with a speed of \(9 \times 10^5 \mathrm{~m} \mathrm{~s}^{-1}\)
  4. D moving towards earth with a speed of \(10 \times 10^5 \mathrm{~m} \mathrm{~s}^{-1}\)
Verified Solution

Answer & Solution

Correct Answer

(B) receding away from earth with a speed of \(10 \times 10^5 \mathrm{~m} \mathrm{~s}^{-1}\)

Step-by-step Solution

Detailed explanation

\(v = c \frac{\Delta\lambda}{\lambda}\) \(v = (3 \times 10^8 \mathrm{~m} \mathrm{~s}^{-1}) \frac{22 Å}{6600 Å}\) \(v = 1 \times 10^6 \mathrm{~m} \mathrm{~s}^{-1} = 10 \times 10^5 \mathrm{~m} \mathrm{~s}^{-1}\) The star is receding away from earth with a speed of…