22. When looking at the radiation emitted by distant stars or galaxies, scientists see emission spectra ‘shifted’ towards the red end of the electromagnetic spectrum—the observed wavelengths are longer than expected'.
Choose the correct statement about this passage.

1. This is known as Planck effect and infrared shift

2. This is known as Compton effect and red shift

3. This is known as Doppler effect and red shift

4. This is known as Compton effect and infrared shift

Correct Answer :

This is known as Doppler effect and red shift