Q. What is the time taken by the earth to complete one rotation about its axis with regard to a fixed star? Answer:
Sidereal day
Notes: Sidereal day is the time taken by the earth to complete one rotation about its axis w.r.t a fixed star Solar day is the time taken by the earth to complete one rotation about its axis w.r.t the sun. Shake is the smallest practical unit of time 1 shake = 10-8s Tropical year: The year in which there is a total solar eclipse.