**fundamental physical constants.**

In my view,

**Physics is the King of Science while Mathematics is the Queen**. Jokes apart, In physical understanding, the values of these mathematical fundamental physical constant define our day to day life. A fundamental physical constant, occasionally referred to as a physical constant is a physical quantity that is believed principally to be universally constant in nature as well as having a constant value in time.

These fundamental physical constant are generally derived from direct observation, either directly such as (the measurement of the speed of light or charge of an electron) or by characterizing a relationship between measurable quantities and then deriving the value of the constant such as (in the case of gravitational constant).

It should be explicitly noted or kept in mind that these fundamental physical constant are written in different units (as preferable while solving a problem), so if you find different sets of physical value that isn’t indeed same as the previous one, then don’t get confused; it maybe has been converted into another set of units.

Literally, fundamental physical constants can be bifurcated into two categories such as

## Dimensioned Fundamental Physical Constants

**Dimensioned Fundamental Physical Constants**is explicitly used to mention those physical constants which are universal in nature. In simple words, those physical constants which are expressed dimensionally as length divided by the time such that it has some units attached; has a numerical value that is precisely dependent on the system of units used.

### 1. __Speed Of Light (C)__

**Ole Christensen Rømer**a Danish astronomer was the first one to demarcate the quantitive measurement of the speed of light in 1676. He was able to demonstrate that light travels at a finite speed which was instantaneously opposed by studying the apparent motion of Jupiter’s moon named Io. After Ole Rømer; in 1865, physicist

**James Clerk Maxwell**represented the speed of light in free space in his world celebrated Maxwell’s Equations, proposing that light is an electromagnetic wave and therefore will travel at speed of light emerged in his Theory Of Electromagnetism.

Nothing Can Travel Faster Than Speed Of Light Credit: BBC.com |

**Albert Einstein**restructured the speed of light in his Special Theory Of Relativity. Einstein postulated that the speed of light is constant with respect to any inertial frame and is independent of the motion of the light source. Einstein showed that the parameter

*c*had applicability outside the context of Light and Electromagnetism.

*c*= 2.99792458 x 10

^{8}meters per second

**❋**(C) entangles space and time. It also appears in the world’s most famous Mass-Energy Equivalence

*E*=

*mc*

^{2}

### 2. __Electric Charge ____(__**e**)

*)*

**e****electric charge**or sometimes referred to as the

**elementary charge**, denoted by (

*), is the electric charge carried by a single photon as well as by single-electron too which has a charge −*

**e**

**e.**Millikan’s setup for the Oil Drop Experiment for measuring Electric Charge Credit: Wikipedia |

In 1909, **Robert A. Millikan** was the first one to measure the magnitude of the elementary charge is his notes Oil Drop Experiment. Though, in 1874, the use of the electric charge as a unit was promoted by **George Johnstone Stoney**; called Stoney Units.

In simple words, as we all know, our modern world basically runs on electricity. Whenever we are talking about the behavior of the electric current or electromagnetism, the elementary charge of an electron is the most fundamental unit

*e*= 1.602177 x 10

^{-19}C

3.

__Electric Constant__

__(ε___{0})**pronounced as (**

*ε*_{0}**“epsilon naught”**) represents the capability of a classical vacuum to permit electric field lines. The physical constant

**also usually called by the name such as**

*ε*_{0 }**electric constant,**

**vacuum permittivity**, or

**permittivity of free space**that associates the units of electric charge to the mechanical quantities such as length and force.

*ε*_{0 }**(**

**“epsilon naught”)**also appears in Maxwell’s Equations, which is used to define the properties of Magnetic and Electric Field and Electromagnetic Radiation.

_{0}= 8.854 x 10

^{-12}C

^{2}/N m

^{2}

^{ }

### 4. __Gravitational Constant (G)__

**Gravitational Constant**or the

**Universal Gravitational Constant**, also known as

**Newtons Constant**was developed as a law of gravity involved in the calculation of Gravitational Effects in Albert Einstein’s General Theory Of Relativity and Issac Newton’s Law Of Universal Gravitation.

Error plot showing experimental values for big G. Credit: Wikipedia |

*m*

_{1}and

*m*

_{2}), and inversely proportional to the square of their distance (

*r*) between them.

The gravitational constant G is a key quantity in Newton’s law of universal gravitation Credit: Wikipedia |

*G*= 6.67259 x 10

^{-11}N m

^{2}/kg

^{2}

### 5. __Planck’s Constant (__*h*)

*h*)

**Max Karl Ernst Ludwig Planck**(known as the Father Of Quantum Physics) commenced the entirely new field in the department of physics named Quantum Physics by his explanations to the solution to the “Ultraviolet Catastrophe” while investigating the Black-Body Radiation problem. While exploring so, he defined a fundamental physical constant, known as Planck’s constant.

While explaining Black-body radiation, Planck derived his famous Plank’s Constant Credit: Wikipedia |

The Planck’s Constant is a fundamental physical constant that was coined for the quantization of Light and Matter. In simple terms, it is an amount of energy in one cycle of the wave from Electromagnetic Radiation, regardless of an associated wavelength.

*h*= 6.6260755 x 10

^{-34}J s

**❋**Planck’s Constant appears in

**Planck-Einstein Relation**that connects photon energy E with its associated wave frequency

**f**

*E = h f***De Broglie Hypothesis**that connects the linear momentum of a particle

**(for every materialistic elementary particle) to the De Broglie wavelength**

*P*

*λ*## Dimensionless Fundamental Physical Constant

__Fine-Structure Constant __**(***α***)**

**(**

*α***)**

**(**

*α***),**is a fundamental physical constant used to outline the strength of an Electromagnetic Interaction between elementary particles such as(electrons, a muon) and light (photons). Almost 100 years ago in 1916, the fine-structure constant

**(**

*α***)**was introduced by a German Theoretical Physicist

**Arnold Johannes Wilhelm Sommerfeld**therefore, being also referred as

**Somerfield fine-structure constant**. For the explanation of fine-structure constant, Somerfield extended the Neil Bohr theory to incorporate elliptical orbits and the relativistic dependence of mass on velocity.

Being a dimensionless physical quantity; currently, the value of the fine-structure constant

**(**

*α***)**having the smallest uncertainty that basically comes from the comparison between the Theoretical Expression

*a*

_{e}(theoretical) and the Experimental value

*a*

_{e}(experimental) of the inconsistent magnetic moment of an electron. The fine-structure constant is considered as a

**coupling constant**for the electromagnetic force similarly as for the other three known fundamental forces or interaction of nature; (gravitational force, weak nuclear force, and strong nuclear force).

list of coupling constant or fine-structure constant

1. Strong force (α

_{s}=≈1)

2. Weakforce (α

_{w}= 10

^{-6})

3. Electromagnetic force (α = 1/137)

4. Gravitational force (α

_{g}= 10

^{-39})

“… there are no arbitrary constants … nature is so constituted that it is possible logically to lay down such strongly determined laws that within these laws only rationally determined constants occur (not constants, therefore, whose numerical value could be changed without destroying the theory).”

Albert Einstein

**All You Need To Know About The Most Relevant Fundamental Physical Constant**

**.**If there are any suggestions, feel free to comment.

*∗*D

*on’t*

*Believe It As I Said Till You Yourself Believe It First – Gautama Buddha*