The 6563 Å line emitted by hydrogen atom in a star is found to be red shifted by 5Å

The 6563 Å line emitted by hydrogen atom in a star is found to be red shifted by 5 Å. The speed with which the star is receding from the earth is

(a) 17.29 x 10⁹ m/s
(b) 4.29 x 10⁷ m/s
(c) 3.39 x 10⁵ m/s
(d) 2.29 x 10⁵ m/s

2.29 x 10⁵ m/s

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PB2002

admin:

AM MOHAN says:

May 2, 2019 at 9:49 am

question it self is wrong
THE CORRECT ONE WILL BE:
Q: The 6563A∘Hα6563A∘Hα line emitted by hydrogen in a star is found to be red shifted by 15∘A15∘A Estimate the speed with which the star is receding from the earth .
−6.86×105ms−16.86×105ms−1−6.86×10−5ms−16.86×10−5ms−1−6.86×105ms−16.86×105ms−1−6.86×10−5ms−16.86×10−5ms−1
Solution : given : λ=6563∘Aλ=6563∘A
Δλ=15∘AΔλ=15∘A
Δλ=−ΔλλΔλ=−Δλλcc
=−156563=−156563×3×108×3×108
=−6.86×105ms−1=−6.86×105ms−1
Answer : −6.86×105ms−1