Question

Question:
On a moonless night, when one looks up the night sky, can spot large number of stars with varying colours. Some appear blue, some appear red, few appear yellow etc. The brightest among them are:

Options:
(1) Blue stars
(2) Red stars
(3) Yellow stars
(4) None of the above

Answer 1

On a clear, moonless night, stars appear in various colors—blue, red, yellow—each indicating a different surface temperature. Blue stars are the hottest and most luminous, followed by white, yellow, orange, and red stars, which are cooler and less luminous.

Science Notes

Evaluation of Options:

1. Blue stars

   • Correct: Blue stars are the brightest due to their high temperatures and luminosities.

2. Red stars

   • Incorrect: Red stars are cooler and less luminous, appearing dimmer than blue stars.

3. Yellow stars

   • Incorrect: Yellow stars, like our Sun, have moderate temperatures and luminosities, making them less bright than blue stars.

4. None of the above

   • Incorrect: Option 1 is correct, so this option doesn't apply.

Answer: (1) Blue stars