The $k$ line of singly ionized calcium has a wavelength of $393.3\ nm$ as measured on earth. In the spectrum of one of the observed galaxies, this spectral line is located at $401.8\ nm$. The speed with which the galaxy is moving away from us, will be

Question

Dr. Abubacker · Accepted Answer

(a) $\frac{\mathrm{\Delta}\lambda}{\lambda} = \frac{v}{c} \Rightarrow \frac{(401.8 - 393.3)}{393.3} = \frac{v}{3 	imes 10^{8}}$
$\Rightarrow v = 6.48 	imes 10^{6}m/s = 6480km/s$

Q. The $k$ line of singly ionized calcium has a wavelength of $393.3\ nm$ as measured on earth. In the spectrum of one of the observed galaxies, this spectral line is located at $401.8\ nm$. The speed with which the galaxy is moving away from us, will be

Explanation

Reviewed by Dr. Abubacker

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