What is the unit for time?

• A. Seconds
• B. Minutes
• C. Hours
• D. Days

Answer: (A)

Time is measured using a standard unit, and in science the base unit is the second. The second is defined very precisely by a specific atomic transition in cesium-133, making it highly reproducible. Because it’s the base unit, other time units are built from it: 60 seconds in a minute, 60 minutes in an hour, and 24 hours in a day. Minutes, hours, and days are still units of time, but seconds are used in science to keep measurements and calculations consistent. When you work with physics equations like speed = distance ÷ time or acceleration = change in velocity ÷ time, using seconds keeps the numbers meaningful and comparable across experiments. If you ever need to handle larger intervals, you can convert them to seconds to simplify the math.