77_constants by digitalsakura

*** from wikipedia ***

the planck constant, or planck's constant, is a fundamental physical constant denoted h , and is of fundamental importance in quantum mechanics. a photon's energy is equal to its frequency multiplied by the planck constant. due to mass–energy equivalence, the planck constant also relates mass to frequency.
in metrology it is used, together with other constants, to define the kilogram, an si unit. the si units are defined in such a way that, when the planck constant is expressed in si units, it has the exact value h = 6.62607015×10−34 j⋅hz−1.
at the end of the 19th century accurate measurements of the spectrum of black body radiation existed, but the distribution of those measurements at higher frequencies diverged significantly from what was predicted by then-existing theories. in 1900, max planck empirically derived a formula for the observed spectrum. he assumed a hypothetical electrically charged oscillator in a cavity that contained black-body radiation could only change its energy in a minimal increment, that was proportional to the frequency of its associated electromagnetic wave. he was able to calculate the proportionality constant from the experimental measurements, and that constant is named in his honor. in 1905, albert einstein determined a "quantum" or minimal element of the energy of the electromagnetic wave itself. the light quantum behaved in some respects as an electrically neutral particle, and was eventually called a photon. max planck received the 1918 nobel prize in physics "in recognition of the services he rendered to the advancement of physics by his discovery of energy quanta".

the boltzmann constant (kb or k) is the proportionality factor that relates the average relative kinetic energy of particles in a gas with the thermodynamic temperature of the gas. it occurs in the definitions of the kelvin and the gas constant, and in planck's law of black-body radiation and boltzmann's entropy formula, and is used in calculating thermal noise in resistors. the boltzmann constant has dimensions of energy divided by temperature, the same as entropy. it is named after the austrian scientist ludwig boltzmann.
as part of the 2019 redefinition of si base units, the boltzmann constant is one of the seven "defining constants" that have been given exact definitions. they are used in various combinations to define the seven si base units. the boltzmann constant is defined to be exactly 1.380649×10−23 j k-1.

*** from britannica ***

decay constant, proportionality between the size of a population of radioactive atoms and the rate at which the population decreases because of radioactive decay. suppose n is the size of a population of radioactive atoms at a given time t, and dn is the amount by which the population decreases in time dt; then the rate of change is given by the equation dn/dt = −λn, where λ is the decay constant. integration of this equation yields n = n0e−λt, where n0 is the size of an initial population of radioactive atoms at time t = 0. this shows that the population decays exponentially at a rate that depends on the decay constant. the time required for half of the original population of radioactive atoms to decay is called the half-life. the relationship between the half-life, t1/2, and the decay constant is given by t1/2 = 0.693/λ.

this ep tells about these three important physical phenomena

Tracklist

1.	01_planckconstant	3:52

2.	02_boltzmannconstant	3:20

3.	03_decayconstant	4:52

4.	04_constants	3:59

Credits

released May 20, 2022

irick neumann
helmut landers
made in logic pro x

License

CC BY-SA 3.0. See the Creative Commons website for details.