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Uses of Dimensional Formula-System of Units

Learn details about the international system of units, international metric system, and about the SI units of different quantities.

When it comes to physics, the International System of Units forms a base. These are the internationally accepted units for measurements and come in two forms- fundamental and derived. The multiple fundamental and derived units are ideal to perform all calculations and measurements using international standards.

Units in Physics

There are multiple systems of units used in physics. Some of the popular ones are SI units, MKS system, FPS system, and CGS systems. Many times students feel confused about the meaning of the SI unit?

The MKS system uses meters, kilogram, and second as the base units. The FPS system is the foot, pound, and the second system for the units of length, weight, and time respectively. The CGS system is the centimetre, gram, second for the units of length, weight, and time respectively.  The SI units are used internationally and define seven base units. Let us know more details about these units.

What is the International System of Units?

The International System of Units is a universally used standard for multiple measurements. Hence, all these units play a crucial role in multiple scientific and development research globally. There are seven base units that can define 22 derived units. The base units are mutually independent while the derived units are the combinations of bases. All these units can be represented as fractional quantities or as the standard multiples. The prefix multipliers range is from 10-24 to 1024.

What is a SI Units List?

SI is an abbreviation of the French word “Systeme International.” This standard system avoids any issues of confusion while considering multiple quantities in scientific and non-scientific research. The top seven SI units are

Sr. No.

Name of unit

SI unit

1

Length

meter (m)

2

Mass

Kilogram (kg)

3

Time

Second (s)

4

Electric current

Ampere (A)

5

Thermodynamic temperature

Kelvin (K)

6

Amount of substance

Mole (mol)

7

Luminous Intensity 

Candela (cd)

What is the SI Base Units List?

The SI base units form the base of any system and are hence called the fundamental units. There are seven SI base units that are mutually independent of each other. These units are

Sr. No.

Name of unit

SI unit

Definition

1

Length

meter (m)

It is defined by taking the fixed value of the speed of light in a vacuum

2

Mass

Kilogram (kg)

It is defined by taking the fixed value of the Planck constant

3

Time

Second (s)

It is defined by taking the fixed value of the Cesium frequency

4

Electric current

Ampere (A)

It is defined by taking the fixed value of the elementary charge

5

Thermodynamic temperature

Kelvin (K)

It is defined by taking the fixed value of Boltzmann constant, k= 1.380649*(10)-23

6

Amount of substance

Mole (mol)

It is defined by the fixed value of the Avogadro constant NA. One mole contains 6.02214076*(10)23 elementary entities

7

Luminous Intensity 

Candela (cd)

It is defined by the fixed value of the luminous efficacy

What is the SI Derived Units List?

The units that are derived from the main seven SI units are called derived units of SI. The dimensions of these units are represented in the dimensions of the base units only. These can be represented as a combination of base and derived both. Some of the widely used derived SI units include

Sr. No.

Name of unit

SI unit

SI unit symbol

Expression in base SI unit

1

Frequency

Hertz

Hz

s-1

2

Electric Potential (Voltage)

Volt

V

kg.m2.s-3.A-1

3

Capacitance

Farad

F

kg−1.m−2.s4.A2

4

Electrical conductance

Siemens

S

kg−1.m−2.s3.A2

5

Magnetic flux

Weber

Wb

kg.m2.s−2.A−1

6

Magnetic flux density

Tesla

T

kg.s−2.A−1

7

Power, Radiant flux

Watt

W

kg.m2.s−3

8

Luminous flux

Lumen

lm

cd

9

Radioactivity

Becquerel

Bq

s-1

10

Force, Weight

Newton

N

kg⋅m⋅s-2

11

Electric charge

Coulomb

C

s⋅A

12

Inductance

Henry

H

kg.m2.s-2.A-2

13

Resistance, Impedance, Reactance

Ohm

Ω

kg.m2.s−3.A−2

14

Energy, Work, Heat

Joule

J

kg.m2.s−2

15

Angle

Radian

rad

m.m−1

Benefits of the international system of units

The main advantages of these SI units include:

  1. It helps in quick learning for students as all units are provided in points that facilitate quick retaining.

  2. It helps students solve different questions related to the SI and CGS units that are quite common in the physics syllabus.

  3. The units and the in-depth knowledge about them help understand deeply about the respective topics.

  4. It helps students learn the units in an interactive manner and can be easily understood to help students gain physics knowledge effortlessly.

Conclusion

So, it is easy to understand all about the international system of units. Starting from the clear definition of these units and to the basic difference between the base and derived units, it becomes easy to understand all about this physics topic.

The SI units are further crucial to do all different measurements and understand their applications in physics. The different advantages of the SI system make it an internationally accredited system for all calculations.

faq

Frequently asked questions

Get answers to the most common queries related to the NDA Examination Preparation.

Why is it necessary to follow a standard metric system?

Answer.It is mandatory to have a standard system for measuring different quantities internationally. It is crucial to provide the same values for i...Read full

What are the main features of the international system of units?

Answer.The main features of any international system of the units depend on the main seven quantities. These quantities include mass, electric curr...Read full

What are the main units in the international system of units?

Answer.The main units in these international systems of measurements include length- meter (m), time- second(s), amount of substance- mole(mole), e...Read full

How is the international system of units fixed?

Answer.The international system of units or the seven basic units is fixed by defining the constants having fixed numerical values when expressed i...Read full

What are the top benefits of the metric system?

Answer.The main advantage of the metric system involves that it is a universally accepted unit of measurement globally. The problems involving diff...Read full