$A$ star emitting radiation at a wavelength of $5000 \; \mathring{A}$ is approaching Earth with a velocity of $1.5 \times 10^6 \; m/s$. The change in wavelength of the radiation as received on Earth is ....... $\mathring{A}$.

In the hydrogen spectrum,the wavelength of the ${H_\alpha}$ line is $656 \ nm$,whereas in the spectrum of a distant galaxy,the ${H_\alpha}$ line wavelength is $706 \ nm$. The estimated speed of the galaxy with respect to the Earth is:

Light from the constellation Virgo is observed to increase in wavelength by $0.4\%$. With respect to Earth,the constellation is:

In the spectrum of light of a luminous heavenly body,the wavelength of a spectral line is measured to be $4747 \ \mathring{A}$,while the actual wavelength of the line is $4700 \ \mathring{A}$. The relative velocity of the heavenly body with respect to the Earth will be (velocity of light is $3 \times 10^8 \ m/s$).

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

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