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

$A$ 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 $v << c$)

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

The Doppler effect in sound,in addition to the relative velocity between the source and the observer,also depends on the individual motion of the source and the observer relative to the medium. However,the Doppler effect in light depends only on the relative velocity between the source and the observer. The reason for this is:

$A$ star is moving away from the Earth with a velocity of $100 \ km/s$. If the velocity of light is $3 \times 10^8 \ m/s$,then the shift of its spectral line of wavelength $5700 \ \mathring{A}$ due to the Doppler effect will be ..... $\mathring{A}$.

Write the formula for the Doppler shift for light.