Hello aspirant

A unit time or midst unit  is any particular time interval used as a standard way of measuring expressing duration. The base unit of time in the international system of units ( SI ) and by extension most of the western world is the second defined as about 9 billion oscillations if the caecium atom.

The shortest unit if time is Planck time. It is the time required for light to travel one Planck lentgh in vaccum.

Hello Aspirant,

Unit refers to 1. Unit time refers to 1 unit, where unit is generally second. So in general we can refer unit time to 1 second. It is in general as the SI unit of time is second. It can also be referred as 1 minute or 1 hour or any other unit of time.