Question

Which of the following is the largest unit of length
(A) millimeter(mm)
(B) centimeter(cm)
(C) meter(m)
(D) kilometer(km)

Answer 1

Hint: The length is measured with the help of a metric system in physics. The most common units that we used while measuring the length in the metric system are millimeter(mm), centimeter(cm), meter(m) and kilometre(km). All are interrelated and interconversion with each other. So first we need to know the definition of each term so as to compare them to get the correct answer.

Complete answer:
Millimeter is a unit of length in the metric system which is equal to one thousand of a meter, SI based unit of length. There are ten millimeters in a centimeter and it is the smallest unit as compared to the other units as per the option given.
Centimeter is a unit of length in the metric system which is equal to one hundred of a meter and here the centi is the SI prefix for a factor of one by hundred. It is greater than millimeters but less than meters and kilometers.
Meter is also a metric measurement which is light that is longer than a yard but smaller than a kilometer. We can define a meter as one thousand kilometers. It is the basic unit in the SI system that is equal to the distance light travels through a vacuum, exactly one by 299792458 seconds.
Kilometre is a unit of length and the largest of all the other three given in the option. It is equal to one thousand meters. As it is the largest unit, it is used to measure distance between geographical places on land.
Hence from the above discussion we can conclude the kilometer is the largest unit of length.
Therefore the correct option is (D).

Note:
Note that there are so many different types of metric units and there are so many of them that are smaller than these four and also larger than these four units.
1km =1000m = 100000cm = 1000000mm
Also remember that One millimeter is equal to 1000micrmeter or 1000000 nanometer, these units are smaller than millimeters.