Prelims 2024

Q. 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?
(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
(c) Statement-I is correct, but Statement-II is incorrect
(d) Statement-I is incorrect, but Statement- II is correct
Correct answer: (d) Statement-I is incorrect, but Statement- II is correct

Question from UPSC Prelims 2024 GS Paper

Explanation:

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

This statement is incorrect. In fact, the opposite is true. Giant stars typically have shorter lifespans compared to dwarf stars. This is because giant stars consume their fuel much more rapidly due to their higher mass and greater gravitational compression in their cores.

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

This statement is correct. Giant stars do indeed have a higher rate of nuclear reactions compared to dwarf stars. This is due to their greater mass, which results in higher core temperatures and pressures, leading to more rapid fusion of hydrogen into helium.

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