Constants
Active in several areas of the COVID-19 pandemic, the Global Publications department at Global Youth Group has always shared accurate and relevant information regarding the coronavirus pandemic and its impact on us today, globally. This article, however, is different from our other articles; it will highlight the interests of math and physics as it explains constants that renown physicists have discovered and utilized throughout the years.
BY KARANVEER SINGH
You must be familiar with Newton’s Gravitational constant or G. It is a fundamental part of mechanics and kinematics. Henry Cavendish first measured G in an experiment performed in the late 18th century, based on Newton’s work. Now, we know G to be approximately equal to 6.67×10−11 m3⋅kg−1⋅s−2.
Physical constants are just constants with units attached to them. But four of them, including the fine-structure constant, inverse fine-structure constant, W to Z mass ratio, and weak mixing angles, do not have any units, that we refer to as physical ratios.
Planck’s Constant, similar to Newton’s gravitational constant, is a physical constant.
It is a significant part of modern physics appearing in Schrodinger’s equations, Heisenberg’s uncertainty principle, Ehrensfert’s theorem, etc. It was calculated by German physicist Max Planck in 1900 (the same year when he published his work on Blackbody radiation). Planck calculated the constant by accurately formulating the distribution of radiation emitted by a blackbody. His hypotheses, referring to light being emitted, absorbed, and reflected in chunks, avoided the UV catastrophe.
h, as aforementioned in the equation above, is equal to 6.62607015 × 10−34 joule second. It has units of Angular momentum which explains the use of ‘reduced h’ as units for the intrinsic angular momentum of particles. Today, we know that h is a link between the energy of a photon and the frequency of a photon. But I’ve been avoiding the use of the word ‘photon’. This is because Planck did not come up with the idea of light as a particle, Einstein did. But without this, Planck’s work would not have been such a big deal.
Another reason why Planck’s constant is important in quantum mechanics is that it is one of the three physical constants used to determine Planck’s length.
Max Planck combined the speed of light, Newton’s gravitational constant, and Planck’s constant in such a way that it gave a length as the result.
The resulting length is an incredibly small number; it is a factor of 10-35( in meters). Planck’s length is too short and anything shorter than that has no physical meaning. It is also the reason why String theory cannot be tested.
References
- Britannica, The Editors of Encyclopaedia. “Planck’s constant”. Encyclopedia Britannica, 1 Jun. 2021, https://www.britannica.com/science/Plancks-constant. Accessed 16 August 2021.
- Stein, J. (2011, October 24). Planck’s constant: The number that RULES technology, reality, and life. PBS. https://www.pbs.org/wgbh/nova/article/plancks-constant/.