If light from a galaxy observed on the earth's surface has a red shift,then:

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 time period of rotation of the sun is $25$ days and its radius is $7 \times 10^8 \ m$. The Doppler shift for the light of wavelength $6000 \ \mathring{A}$ emitted from the surface of the sun will be ...... $\mathring{A}$.

If a star emitting light of wavelength $5000\,\mathring{A}$ is moving towards Earth with a velocity of $1.5 \times 10^6\,\text{m/s}$,then the shift in the wavelength due to Doppler's effect will be......$\mathring{A}$

$A$ rocket is moving towards the moon with a speed $v$. The astronaut in the rocket sends signals of frequency $f$ towards the moon and receives them back after reflection from the moon. What will be the frequency of the signal received by the astronaut? (Assume $v << c$)

$A$ 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)