$A$ heavenly body is receding from Earth such that the fractional change in wavelength $\lambda$ is $1$. What is its velocity?

Hubble showed that the universe as a whole is expanding and the distant stars are receding from us. The spectral line from a star,when compared with the corresponding line from a stationary source,will then show:

The $6563 \ \mathring{A}$ line emitted by a hydrogen atom in a star is found to be red-shifted by $5 \ \mathring{A}$. The speed with which the star is receding from the Earth is:

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency $10 \ GHz$. What is the frequency of the microwave measured by the observer? (Speed of light $c = 3 \times 10^8 \ ms^{-1}$)

The sun is rotating about its own axis. The spectral lines emitted from the two ends of its equator,for an observer on the earth,will show

If the shift of wavelength of light emitted by a star is towards the violet end of the spectrum,then this shows that the star is