QJEEM22Ph0c5f: JEE Main 2022 Physics - Class 12 JEEM22Ph0c5f Solution: For a specific wavelength 670 nm of light coming from a galaxy…

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For a specific wavelength 670 nm of light coming from a galaxy moving with velocity v, the observed wavelength is 670.7 nm. The value of v is :

Accepted Answer

${\lambda _{obs}} = {\lambda _{source}}\sqrt {{{1 + {v \over C}} \over {1 - {v \over C}}}}$

For $v < < C$ ,

${{670.7} \over {670}} = 1 + {v \over C}$

$\Rightarrow v = {{0.7} \over {670}} \times 3 \times {10^8}$ m/s

$\Rightarrow v \simeq 3.13 \times {10^5}$ m/s

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