Question:
For a specific wavelength 670 nm of light from a galaxy moving with velocity ν, the observed wavelength is 670.7 nm. The value of ν is
For a specific wavelength 670 nm of light from a galaxy moving with velocity ν, the observed wavelength is 670.7 nm. The value of ν is
Updated On: Feb 2, 2026
- 3 × 108 ms–1
- 3 × 1010 ms–1
- 3.13 × 105 ms–1
- 4.48 × 105 ms–1
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The Correct Option is C
Solution and Explanation
The correct answer is (C) : 3.13 × 105 ms–1
λobs = λsource \(\sqrt{\frac{1+\frac{ν}{C}}{1-\frac{v}{C}}}\)
For ν << C,
\(\frac{670.7}{670}\) = 1 + \(\frac{ν}{C}\)
⇒ ν = \(\frac{0.7}{670}\) × 3 × \(10^8\) m/s
⇒ ν ≃ 3.13 × \(10^5\) m/s
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