Physics 0625 · Question 1[9 marks]
Stars undergo significant changes from formation to their final remnant stage.
(a)[3]
Define the astronomical unit "light-year" and calculate the distance of 1 light-year in metres. (Speed of light c = 3.00 × 10⁸ m s⁻¹, 1 year = 365.25 days).
(b)[2]
Explain how a main sequence star remains stable for billions of years, identifying the two opposing forces acting on the star.
(c)[4]
Describe the life cycle of a star with a mass much greater than the Sun after it leaves the main sequence, naming the intermediate stage, the explosive event, and the possible final remnants.