10 questions · Form 2 Science Bab 10: Stars and Galaxies in the Universe
Why does a star stop shining at the end of its White Dwarf stage?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Why does a star stop shining at the end of its White Dwarf stage?
Answer: B
A white dwarf no longer undergoes nuclear fusion; it slowly radiates its remaining heat into space until it completely cools.
2. What catastrophic cosmic explosion occurs when a supermassive star dies?
Answer: B
When a massive or supermassive star exhausts its nuclear fuel, its core collapses rapidly, causing a violent supernova explosion.
3. What will be the final remnants of a medium-sized star like our Sun at the end of its life cycle?
Answer: C
After expanding into a Red Giant and casting off its outer layers as a planetary nebula, a medium-mass star cools down to become a White Dwarf.
4. Which star color indicates the HOTTEST surface temperature?
Answer: D
Blue stars have the highest surface temperatures (ranging from 25,000 K to over 50,000 K), whereas red stars are the coolest.
5. Which factor does NOT directly determine the brightness of a star as observed from Earth?
Answer: D
Apparent brightness depends on physical size, luminosity (surface temperature), and distance from Earth. Moons do not affect stellar brightness.
6. The Large Magellanic Cloud is classified under which type of galaxy?
Answer: C
The Large Magellanic Cloud and Small Magellanic Cloud are satellite galaxies of the Milky Way classified as irregular galaxies.
7. What unit of distance is defined as the distance traveled by light through a vacuum in one earth year?
Answer: B
A light-year (ly) is a unit of astronomical distance equal to the distance light travels in one year (approx. 9.5 trillion km).
8. Which of the following stars would have a surface temperature closest to approximately 5,500°C - 6,000 K?
Answer: B
Our Sun is a yellow main-sequence star with a surface temperature of around 5,700 - 6,000 Kelvin.
9. Which physical process powers a main sequence star and generates light and heat energy?
Answer: B
In a star's core, extreme temperature and gravitational pressure fuse hydrogen nuclei into helium through nuclear fusion, releasing immense energy.
10. On which specific outer arm of the Milky Way galaxy is our Solar System located?
Answer: C
Our Solar System resides on a minor spiral arm of the Milky Way called the Orion Arm (or Orion Spur).