Four different main-sequence stars are colored blue, orange, red, and yellow. What is their rank from coolest to hottest?
A) red, yellow, orange, blue B) blue, yellow, orange, red
C) red, orange, yellow, blue D) orange, blue, yellow, red
Question 2
When an unstable nucleus decays by emitting an alpha particle, the atomic number Z of the nucleus
A) increases by 4.
B) increases by 2.
C) decreases by 2.
D) decreases by 4.
E) remains unchanged.