Q. Which star is the coolest based on color?
Answer: Red
Notes: The color of the star measures its temperature. The red star is the coolest and blue the hottest based on the Wien's displacement law.

This question is part of 40000+ General Studies MCQ Series Course on GKToday Android app. Question Number: 164 in Astronomy - Universe, Constellations & Galaxies, Stars in above course in App.