Question

The difference in the length of a mean solar day and a sidereal day is about

• A. $1$ minute
• B. $4$ minute
• C. $15$ minute
• D. $56$ minute

Answer 1

The correct option is B $4$ minute

Solar day is the time taken by earth to complete one rotation about its axis with respect to sun. Sidereal day is the time taken by earth to complete one rotation about its axis with respect to distant star. There is a difference of $4$ minutes between solar day and sidereal day. Solar day is longer as earth has to rotate greater angle to attain same position with respect to sun due to its own motion (revolution) round the sun. Its position with respect to distant star remains almost fixed.