If a star's spectral lines are shifted towards the red end of the spectrum, then the star is

Question

A moving towards Earth.

B moving away from Earth.

C moving at the same rate as Earth.

D none of the above.

Answer 1

B

Doppler shift - if an object is moving away, it's light will lose energy (since they have to overcome the momentum of the object heading that is receding).

This is a very common technique in astronomy, and it's also how radar detectors work - the police bounce a photon (laser, microwave, etc.) off your car, and the speed of your car shifts the spectrum - they measure the shift to get your speed.

If an object is moving toward you (or you toward an object), it is blue shifted.

Answer 2

It is moving away which will increase wavelength and shift color towards red.

Answer 3

b, moving away

Answer 4

google "Red shift" and you get "An observed redshift due to the Doppler effect occurs whenever a light source moves away from the observer"

that was hard

Answer 5

Hmmm.  Ansy, it appears that this string of questions is an attempt by you to get other people to answer school questions for you, that you have been given the means to study on your own.  This is cheating.  It's a violation of the academic honor code of any school. You should do the rest on your own, now.