$A$ star emits light of $5500 \ \mathring{A}$ wavelength. If it appears blue to an observer on the Earth,it means:

When the wavelength of light coming from a distant star is measured,it is found to be shifted towards the red end of the spectrum. What is the conclusion?

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......$km/sec$.

$A$ star emitting light of wavelength $5896 \ \mathring{A}$ is moving away from the earth with a speed of $3600 \ km/s$. The wavelength of light observed on earth will be:
($c = 3 \times 10^8 \ m/s$ is the speed of light)

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

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 ...... $\mathring{A}$.