At the end of the day, let us sigh out a breath of tranquility, sit down while sipping a glass of wine and go trying to set somethings about “quantum physics” under some rational history light.
Beforehand, let us
put it out clear for once and for all that a quantum (a Latin word which plural is quanta) is the smallest discrete unit of a phenomenon. For example, a quantum of light is a photon,
and a quantum of electricity is an electron. The word quantum comes from Latin, meaning "an amount". If
something is quantifiable, then it can be measured.
Well, there are
some interesting events we could bring here to help us shed simple
non-mathematical light on some of the reasons the idea of energy quanta was brought in. We will pick the photoelectric effect, a study that
ultimately claimed the 1921 Nobel Prize for Albert Einstein (1879 – 1955), who
was not an enthusiast of “quantum physics”,
despite of taking the quantum concept of energy to help explaining his theory
on the above mentioned effect.
The problem: It
was noticed that when electromagnetic radiation (like light for instance) is
incident on a metal surface, transference of energy to the irradiated electrons
occurs. According to classical physics a lag between irradiation and subsequent
emission of some of the electrons would take place. But it simply does not
materialize, because the transference happens “instantly”, in frontal contrast
with the prediction by classical physics. Mean, there is not a “time lag” for
the electrons to acquire the incident energy. In other words, emission takes place as soon as the
light shines on the surface; there is no detectable delay.
Einstein defended
that the energy transference is a function of the incident radiation frequency
and its relation with the so-called frequency threshold of the metal surface.
So, if incident radiation frequency is of a value below that threshold, it will
not be able to promote electrons ejection from the metal surface. Looking at
the practical aspects of the problem, Einstein moved to the conclusion that the
energy transference occurs under the form of “unitary blocks” or “quanta”. And he extended the ad hoc relation fist devised by Max
Planck to express quantitatively the amount of energy transfer: E = h 𝛎, where
E is the energy, 𝛎 f its frequency, and h is the Planck’ s constant, given in the MKS as 6.62607015 × 10-34 m2 kg/s.
References:
1. BYJUS; https://byjus.com/question-answer/why-photoelectric-effect-cannot-be-explained-by-the-classical-physics/
; (accessed on February 10, 2023);
2. Wikipedia; Albert Einstein; https://en.wikipedia.org/wiki/Albert_Einstein
; (accessed on February 10, 2023);
3. https://socratic.org/questions/what-was-einstein-s-explanation-for-the-photoelectric-effect ; (accessed on February 10, 2023)
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