Question

1 mean solar day = _________ s

• A. 8640000
• B. 86400
• C. 8640

Answer 1

The correct option is B

86400

1. A solar day is the time it takes for the Earth to rotate about its axis so that the Sun appears in the same position in the sky, which is equal to 24 hr.
2. The time between two successive passage of the mean sun across the meridian at noon is known as Mean Solar system.
3. Mean Solar day equals to 1 day.
4. 1 day = 24 hour = 24 x 3600 seconds = 86400 sec
5. Mean solar time is the time taken by the earth to make one complete rotation about its own axis.

So, 1 second is $\frac{1}{86400}$ part of a mean solar day.