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

The periodic time of rotation of a certain star is $22$ days and its radius is $7 \times 10^8 \ m$. If the wavelength of light emitted by its surface is $4320 \ \mathring{A}$, the Doppler shift will be $(1 \ day = 86400 \ s)$

$A$ spectral line $\lambda = 5000\ \mathring A$ in the light coming from a distant star is observed as $5200\ \mathring A$. What will be the recession velocity of the star?

The $6563\,\mathring{A}$ $H_{\alpha}$ line emitted by hydrogen in a star is found to be redshifted by $15\,\mathring{A}$. Estimate the speed with which the star is receding from the Earth.

If a star emitting yellow light is accelerated towards the Earth,then to an observer on Earth,it will appear:

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..... $km/s$.