What are Constants in Physics?
The significance of constants in Physics is that throughout all of the formulations of the basic theories of Physics and the application to the real world, physical constants appear as fundamental invariant quantities, and they have specific and universally used symbols, that are of such importance that they must be known to as high an accuracy as is possible.
The physical constant also called the fundamental constant or the universal constant is a physical quantity that is believed to be universal in nature and has a constant value at all times.
Fundamental Constants in Physics
Speed of light in vacuum = c
Planck’s constant = h
The electric constant = ε0
The elementary charge = e
Constant Value in Physics
In physics, we deal with various dimensions, and to set the dimensions of an entity, the time length of an event, or the density of the fluid we need to compare them with other entities, we use as a reference. These entities are the constants of physics, such as the speed of light (c), the charge of the electron(e) or mass (mp) of a proton, Rydberg constant, and so on.
For example, the value of Avogadro's number is 6.02214 x 10²³ mol⁻¹ remains the same everywhere.
Important Physical Constants
There are various fundamental constants to describe the universe as completely as possible; a few are listed below:
Table: List of All Constants in Physics
All physics constants
Table: All Constant Values in Physics
Famous Constants in Physics
There are so many constants besides those I mentioned above, but some constants in physics are recognized widely.
Constant values in physics that are most popular among all the physical constants are as follows:
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The physical constant is a complex concept that is taught in class 11 physics. This is based on the curriculum set by the Central Board of secondary education and physical constants or Constance of Physics holds a significant weightage in the examination and therefore are extremely important to understand. The concept of physical constants can be studied in depth in the study notes that I provided by Vedanta, these notes are repaired by Vedanta’s export research team who are well-versed in research and curating study notes for students, Vedantu’s exports have extensive experience and have done thorough research in the duration of these study notes. The notes provided by Vedanta are based on the latest CBSE curriculum and are therefore up to date.
Physical constants are known by different titles such as fundamental constant, universal constant, Constance of physics. It is extremely important to have an accurate evaluation of the physical constants as their accuracy will help to check how up to the mark the theories are, as they form the basis of Physics their accuracy allows useful applications that can be made based on certain theories.
Physical constants are a set of fundamental quantities that appear in the basic theoretical equations of physics.
For example, a universal constant of nature is the speed of light in a vacuum (c). The speed of light can be studied in both electromagnetic theory and in relativity theory; in relativity theory, it relies on energy to Mass whose equation can be written as E =mc2. The value of the speed of light never changes and it does not depend on any experimental conditions like the speed of a sound wave changes in some cases therefore, the speed of light is a universal constant
Table Representing Some Important Physical Constants
FAQs on Constants in Physics
1. What are physical constants?
In simple words, physical constants can be defined as constants whose value remains the same, that is they have a universal value that never changes as a result of any experiment or any theory. Physical constants are used to check the accuracy of various theories. Some of the important physical constants are speed of light in a vacuum (c), charge on the electron ε0, Planck’s constant (h), gravitational constant (G).
2. Where can I find the study material related to physical constants?
The study material related to physical constants can be easily accessed by visiting Vedantu’s website. These notes are prepared by Vedanta‘s research team who are well versed in the study of Physics and have done extensive research and analyzed previous year's question papers and then tailored the study notes according to the students’ needs. These notes that Vedanta provides are based on the latest CBSE curriculum and can help students to score excellent marks in the examination. The study notes are available for free and can be downloaded in a PDF format, after downloading the PDF students can enjoy hassle-free learning as they can study in an offline environment which is the most suitable option for concentration. The study notes are written in an extremely simplified language which makes the learning process as easy as ABC.
3. What are the fundamental constants in physics?
The basic fundamental constants in Physics are as follows-
Speed of light in vacuum = c
Planck’s constant = h
The electric constant = ε0,
The elementary charge = e
4. How to learn physical constants?
It is extremely difficult to learn all the physical constants however students can learn the most basic physical constants and the only way to do this is by revision and practice. Students should practice every day the basic physical constants that will help them to learn more easily. Students can make tables and keep them at a place where they can see them several times in a day. This will help them to efficiently memorize many formulas and symbols.
5. List some important constants in physics.
Table: List of All Constants in Physics
S.no | Name | formula | Value |
1 | Von Klitzing constant | Rk = 2πh/e² | 25812.80745...Ω |
2 | Curie constant | C = X (T - Ө) | 1.3047 K * A/(T * m) |
3 | Fine-structure constant | α = e²/2hcε0 | 0.007297351 |
4 | Compton wavelength | λ = h/mc | In meter: 2.42 x 10⁻¹²m In Angstrom = 0.242 Å |
5 | Impedance of free space | Z0 = 1/ε0c0 | 376.730...Ω |
6 | Bohr radius | a0 = 4πε0 h²/e²mₑ | 0.0529 m |
7 | Faraday constant | F = eNA | 96,485 C/mol |
8 | Vacuum electric permittivity | ε0 = 1/μ0c² | 8.854 x 10⁻¹² F.m |
9 | Stefan–Boltzmann constant | σ = π²k⁴/60h³c² | 5.67 x 10⁻⁸Js⁻¹m⁻²K⁻⁴ |
10 | Thomson cross-section | σe = (8π/3)re² | 6.6524587321 x 10⁻²⁹ m² |
11 | Vacuum magnetic permeability | μ0 | 1.25663706212(19)x10⁻⁶N. A⁻² |
6. Is MU a Physical Constant?
Yes, MU is a physical quantity. It is pronounced as mu naught or mu zero and symbolized as μ₀. The μ₀ is commonly called the permeability of free space, vacuum permeability, the permeability of vacuum, or the magnetic constant. Its value is,
μ₀ = 4π x 10⁻⁷ H/m ≈ 12.57 x 10⁻⁷ H/m
7. Are Constants Dimensionless?
The dimensionless physical constants are the pure numbers because they don’t have any units attached to them, and they are independent of whatever system of units used.
For example, the formula for the specific gravity is defined as the density of the substance divided by the density of water at 4oC. Therefore, the units of density cancel out each other, and the term specific gravity becomes a dimensionless quantity.
8. What are the Physical Quantities? Give Some Examples.
The quantities in physics that are measurable are called physical quantities.
Such quantities are force, mass, velocity, light intensity, and many more.
9. What are the Two Types of Physical Quantities?
The two types of physical quantities are:
Fundamental or basics quantities, and
Derived quantities.
