Q. When does the entire earth experience equal days and nights?
Answer: Day of equinox
Notes: Equinox literally means "equal night", giving the impression that the night and day on the equinox are exactly the same length; 12 hours each. There are two equinoxes every year, in March and September. When the Sun shines directly on the equator, and the length of night and day are nearly equal.

This question is part of 40000+ General Studies MCQ Series Course on GKToday Android app. Question Number: 51 in Climatology - Climatic Classification in above course in App.