UPSC Previous Year Question | Prelims GS | 2024

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.

Answer

Correct Answer

Statement-I is incorrect, but Statement-II is correct.

Explanation

Statement-I is incorrect because massive, luminous giant stars generally consume their nuclear fuel much faster and therefore have shorter lifetimes than low-mass dwarf stars such as red dwarfs. Statement-II is correct in the intended comparison: giant stars, particularly massive ones, have higher luminosities and greater rates of energy production through nuclear reactions. Option A is incorrect because Statement-I is false. Option B is incorrect for the same reason. Option C is incorrect because Statement-II is not false. Thus, option D is correct.

Topics: astronomy, science and technology, stellar evolution, stellar lifetime and nuclear fusion