Constants in physics synonymous to physical constants sometimes Universal constants or fundamental physical constants is the physical quantity or entity which are believed to have a constant value in time and are universal.
Nature Of Physical Constants
Based on nature, the fundamental constants are grouped into three categories namely-
- A: Characteristic of a particular system. (Characteristic of light)
- B: Characteristic of a class of physical phenomena. (Characteristic of electromagnetic phenomena)
- C: Universal Constants. (Discovered after the discovery of special relativity)
Few Physical constants can take the dimensional form like – speed of light; in contrast, few are dimensionless like- fine structure constant. Some physical constants are material constants which means they possess constant value for a material.
A constant can be expressed using multiple equivalent units like – SI, natural units, atomic mass unit, CGS units etc. Some physical constant redefined by fixing the SI values. But this certainly increases the uncertainty in the value of physical constants.
Number Of Fundamental Constants
There is no ground rule defining the number of physical constants in physics. The number varies in accordance with the accepted physical theory.
The table given below comprises the list of physical constants –
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