The observed spectral lines of a star are all shifted towards the red end of the spectrum.Which statement is true?
A)This is an example of the photoelectric effect.
B)This is an example of the Doppler effect.
C)The second law of Kirchhoff explains this.
D)The star is not rotating.
E)The star has a radial velocity towards us.

Question

Quizplus · Accepted Answer

The observed shift towards the red end of the spectrum is indicative of a shift in wavelength caused by the motion of the star. This is an example of the Doppler effect. The observed shift towards the red end of the spectrum is known as a redshift, which is an example of the Doppler effect. It occurs when there is a relative motion between the observer (us) and the source (star), causing a shift in the wavelength of the emitted light. This shift towards the longer wavelengths (red end of the spectrum) indicates that the star has a radial velocity towards us.

The Observed Spectral Lines of a Star Are All Shifted