Question

Why Time is a scalar quantity?

Answer 1

Hint: In Physics we study about physical quantities, there are two types of quantities one is vector and second is scalar. Scalar quantities are those in which we need only magnitude to describe that quantity. For example - speed, mass etc. Vector quantities are those which need direction as well as magnitude to describe that quantity. For example - velocity, force etc.

Complete answer:
Time is a scalar quantity. Because we need only magnitude to describe time. Now the question arises that we have a direction of time like past to present, present to future. Then why don't we consider this direction for time to take time as a vector. For this question we need to understand the basic concept of vectors.
In our science we describe those quantities as vectors which have direction, where "direction" in this context means a direction in three dimensional space. Time clearly has no such direction. That’s why time is not a vector quantity. It needs only magnitude.

Note:
Time is not the only physical quantity which creates an illusion of vector. There are a few physical quantities which also fall under this category. Like Electric Current. Electric current also has a direction from positive terminal to negative terminal. But as we discussed above it does not have direction in three dimensional space. So it is a scalar quantity.