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

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 $3 \times 10^8 \ m/s$).

$A$ 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 $v << c$)

The Doppler effect is applicable for

The apparent wavelength of the light from a star moving away from the Earth is $0.01\%$ more than its real wavelength. Then the velocity of the star is......$km/sec$.

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 $(1 \ day = 86400 \ s)$