Question

An astronomer observes a redshift due to the Doppler effect in the spectrum of a nearby star. What does the redshift indicate about the star’s movement and change in frequency?The star is not moving with no change in frequency.⊝The star is moving toward the observer with an increase in frequency.⊝The star is moving away from the observer with a decrease in frequency.⊝The star is moving toward the observer with a decrease in frequency.

Answer 1

When an object is moving away from Earth or observer, it expresinces a red shift in the wave spectrum. Which means that the wavelength is stretched or wavelength is increased, which results in decrease in frequency and energy of photons.

Therefore, option (c); the star is moving away from the observer with a decrease in frequency, is the correct choice.