Question

the doppler effect is used to measure the speed of galaxies. *
true
false

if a galaxy has a greater red shift than another...... *
it is moving faster
it is moving slower
it is no longer on the main sequence of an h-r diagram
it is turning into a black hole

Explanation:

First Question (The Doppler Effect is used to measure the speed of galaxies)

The Doppler Effect (specifically cosmic redshift) is used to measure the speed of galaxies. When a galaxy moves away from us, the light it emits is redshifted (shifted to longer wavelengths), and the amount of redshift can be used to calculate its recessional velocity (speed away from us). So the statement is true.

Redshift in the context of galaxies is related to the Doppler Effect (and cosmic expansion). A greater redshift means the light from the galaxy is stretched more, indicating a higher recessional velocity (the galaxy is moving away faster). The other options are incorrect: a greater redshift doesn't relate to being on the H - R diagram (which is for stars) or turning into a black hole, and a greater redshift means faster, not slower, motion.

Answer:

True

Second Question (If a galaxy has a greater red shift than another......)