(Note that different students may see different quiz forms.)
Giant stars are rare because a) they do not form as often as main sequence stars. b) giant stars are unstable. c) the giant stage is very short compared to the main sequence stage. d) elements heavier than helium are relatively rare.
In a color-magnitude diagram of a star cluster, the blue end of the main sequence is useful for defining the age of the cluster because a) blue stars are not affected by extinction and reddening by dust. b) stars just slightly brighter and redder are just now evolving off the main sequence to become giants. c) older, metal-poor stars are blue. d) the hottest stars are the oldest stars in a cluster.
Your NAME (required for credit!)
How confident are you about your answers? 1) Guessing! 2) Some idea. 3) Good idea. 4) Pretty sure. 5) Absolutely certain.
Any comments or questions about these questions?
Please only press the Send button once!