Units and Dimensions

Each and every physical quantity known until day can be expressed in terms of seven fundamental quantities by calculations and relationships by using units and dimensions in physics. Units can be defined as the standard amount of a quantity for measuring physical

quantities. Since there are many types of measurable quantities, there are many types of units. The importance of dimensions and units can be seen mainly through dimensional analysis establishing the correlation or connection between one physical quantity and the other physical quantity. In this article, we collected some brief information on the concept of units and dimensions in physics, the importance of dimensions and units separately? And some find the directions of acceleration and many more physical quantities.

What Are Units And Dimensions In Physics?

Units and dimensions in physics are two sides of a coin. They go together because a unit is nothing without a dimension and vice versa. Units are the describing part for any physical quantity because it gives us the exact measurement of that physical quantity so that everyone can understand and relate to the actual measurement of the quantity. 

A person living in Greenland would understand the meaning when a person living in the U.K. will tell him that the sun’s distance from the earth is 0.00001573 light-years. He knows that distance and length can only be measured by meters and kilometers. The man of Greenland will argue that the sun is 150 million kilometers from the earth. Here comes the role played by units. Both light-years and kilometers are physical units that denote the distance between one and the other object. We will learn more about the conversion of units and different unit systems adopted globally.

On the other hand, dimensions have very rigid support in determining the existence of a physical quantity. The physical quantity “acceleration” is only acceleration if the dimensions of acceleration fit in it and it is mathematically correct. Dimensions are the core part of any physical quantity of mathematical relevance. We will learn about applications of dimensions in the form of dimensional analysis and why dimensional analysis is essential that much?

Base Units And Derived Units

A base unit or a fundamental unit is the unit used to measure base quantities. Base quantities are those quantities that can be conventionally chosen as a subset of some physical quantities. Derived units can be defined as those units of measurement formed due to the multiplication and division of the base units without fixed numerical factors.

Types Of Units

SI units

The longer abbreviation of the units is the International System of Units. It’s the most recent and modern metric system used throughout the world. It is often used as the standard unit if

measurement.

It mainly contains seven units of measurement, which are:-

• Second (s) is used as a unit to denote the measurement of time.
• Meter (m) is the unit to indicate the measurement of length.
• For measuring mass, a kilogram (kg) is used as a unit.
• Electric current is measured by the unit of ampere.
• For measuring the temperature, kelvin (k) is used as a unit.
• Mole is the unit used to denote the amount of substance.
• The latest entry was of candela(cd), which is used for measuring luminous intensity

MKS units

The full form of this system is meter, kilogram, and second. This metric system is used to denote the measurement of physical quantities. Here meter is used to represent length; a kilogram is used to indicate mass. It set the base for the SI units before they were redefined.

What is the Dimensional Formula?

In terms of dimensions, a dimensional equation is an equation that connects fundamental and derived units. The three base dimensions in mechanics are length, mass, time, temperature, and electric current, with the fundamental units being the meter, kilogram, second, ampere, kelvin, mole, and candela. In any dimensional equation, the dimensional formula of different quantities is employed to construct a link between them. The following is an example of a dimensional equation: 

The dimensions of acceleration will be equal to the dimension of velocity divided by the dimensions of time.

Acceleration = [M0L1T-2]

The Importance Of Dimensions And Units

The importance of dimensions and units can be seen by dimensional analysis. The characteristics of physical quantities are described by the dimensions of base quantities and their combinations. Dimensional analysis can be used to recheck the equations for dimensional consistency, deduce relationships between distinct physical amounts, etc.

A dimensionally consistent equation must not be perfect or correct, whereas a dimensionally incorrect or inconsistent equation must be wrong.

Dimensional analysis has a wide range of applications.

To change a physical quantity’s value from one standard to another.

To ensure that a particular relationship is correct.

To come up with a relationship between different physical quantities.

Conclusion

Units and dimensions are the building backbone of entire mechanical physics. If there were no units and dimensions in physics, there would have been no tool to accurately measure and use those measurements of the physical quantities to deduce the laws. We cannot imagine the importance of units and dimensions in this subject. You learned what units and dimensions in physics, and what is the importance of dimensions and units?