$A$ galaxy is moving away from the Earth such that a spectral line at $600 \ nm$ is observed at $601 \ nm$. Then,the speed of the galaxy with respect to the Earth is (in $km \ s^{-1}$)

$A$ star moves away from Earth at a speed of $0.8 c$ while emitting light of frequency $6 \times 10^{14} \text{ Hz}$. What frequency will be observed on the Earth (in units of $10^{14} \text{ Hz}$)? ($c$ is the speed of light)

The wavelength of light observed on the earth,from a moving star is found to decrease by $0.05\%$. Relative to the earth,the star is:

Due to the Doppler effect,the shift in wavelength observed is $0.1\;\mathring{A}$,for a star producing a wavelength of $6000\;\mathring{A}$. The velocity of recession of the star will be ....... $km/s$.

The $K$ line of singly ionised 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..... $km/s$.

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 ............