UPSC Prelims 2024 · Question 92 of 97

UPSC Prelims 2024 question on Giant Stars Lifespan

Consider the following statements:

Statement-I:
Giant stars live much longer than dwarf stars.

Statement-II:
Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.

Which one of the following is correct in respect of the above statements?

  1. Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
  2. Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  3. Statement-I is correct, but Statement-II is incorrect
  4. Statement-I is incorrect, but Statement-II is correct
Show answer

Answer: D. Statement-I is incorrect, but Statement-II is correct

Verdict

Correct answer: Statement I is incorrect, but Statement II is correct → Option (d).

Analysis

Hence Statement I is not correct (giant stars live shorter, not longer) and Statement II is correct.

Statement by statement

Statement I – INCORRECT: Giant stars have masses from eight times to as much as 100 times that of our sun. These massive stars have hotter and denser cores than dwarf stars. Therefore, giant stars have a greater rate of the nuclear reactions that light up stars. Massive stars also use up the hydrogen fuel in their core faster, despite starting out with much more of it, meaning they live much shorter lives than dwarf stars.

Statement II – CORRECT: Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.

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