Question

SI unit of distance is
(a). m
(b). cm
(c). km
(d). None of these

Answer 1

Hint: Revise the SI system of measurements. It has seven fundamental units. Check if the unit to measure distance is also fundamental or not. If it is fundamental then you can directly find the unit of distance from the list. If not then you can derive the unit.

Complete answer:
The metre is the base unit of length in the International System of Units (SI). The SI unit symbol of length is m. Distance is the path or the length covered by a body that is moving from one place to another. Thus, we can say that metre is Internationally used to measure distance. If we want to obtain the unit of quantities other than fundamental quantities then we can derive them using base units only.
Another common unit used to measure distance in kilometers. It is generally used when we talk about distance between two states or countries.
We can find long distances like from earth to stars or to moon. It is measured in light years. This unit is the distance in which light travels for one year.

Note: Distance and displacement are related to each other so do not get confused between two. Distance is scalar quantity and displacement is vector quantity. Other options cm and km are also units of distance or length. But they are not S.I. units. Centimeter is used to measure small lengths like the length of a book, mobile. While kilometer is used to measure larger distances like distance between places.