A clock has 12 digits and two needles. Each digit in the clock represents the time. The smaller needle is hour hand and the bigger needle is minute hand. When the smaller needle moves from one digit to the next digit we say 1 hour is complete. Smaller needle will take 12 hours to complete one full circle.
When the minute hand completes one circle, we say it has completed 60 minutes. 60 minutes will make an hour and 24 hours will make a day. That means, the hour hand should complete two rounds to the clock.