Planck’s Quantum Theory

Most natural phenomena could be made clear by Newton’s Laws of classical mechanics or classical theory by the end of the 19th century, thanks to the work of scientists. Until this point, matter and energy were seen as separate entities with no connection to one another. In 1873, Scottish physicist James Clerk Maxwell published his Maxwell equations, which enable scientists to characterize the qualities of radiant radiation. The photoelectric effect and other phenomena like black body radiation could not be explained by classical theory or mechanics until the twentieth century. German scientist Max Planck developed his quantized energy theory of electromagnetic waves during this period. Let us now discuss planck’s quantum theory in detail.

Planck’s Quantum Theory

                                                                              Planck’s Quantum Theory

Plancks Quantum Theory Presuppositions

When it comes to radiation, Planck’s quantum theory is the best way to go. Planck’s quantum theory has the following presuppositions:

  • Discrete packets or bundles of energy are emitted or absorbed intermittently by matter.
  • Quantum is the name given to the smallest bundle or packet of energy. Using light as an example, a photon is a quantum of light.
  • The absorb quantum energy is proportional to the radiation frequency.

Quantization of Energy

In quantum physics, energy is construed as occurring in discrete “packets,” or photons, at the subatomic level. Photons appear in a variety of denominations, much like paper money.

Photons are energy bundles in quantum physics, and they correspond to various hues in the visible spectrum and other forms of electromagnetic radiation (radio waves, microwaves, X -rays, etc).

The energy value of a red photon is distinct from that of a blue photon. Red and blue photons, like dollar note denominations, are quantized in the same way. Each photon carries a discrete quantity of energy that is all it is own.

It is similar to Plank’s constant, which describes “how quantum” energy may be, that energy is unique or “quantized.”

Electromagnetic Radiation

The phenomena of electromagnetic waves travelling across space do refer to as electromagnetic radiation. A medium isn’t necessary for the propagation of electromagnetic waves. When the electric and magnetic components of a wave interact with one another, the radiation is prolonged. The planes of both components are perpendicular.

Electromagnetic waves all share a set of characteristics. The frequency and wavelength of electromagnetic radiation may be used to classify it. There are three types of waves that are higher in frequency than visible light, which are x-rays, gamma rays, and UV rays. Infrared rays, radio waves, and microwaves are examples of waves with a lower frequency than visible light.

Black Body Radiation

All the radiation that falls on it is lost by the dark body. All frequencies of radiation can be caught and exhaled by a perfect black body. Temperature affects the emission of electromagnetic radiation from a black substance. Using Planck’s law, a black body’s emitted radiation may be termed by its frequency variation. Planck’s radiation, a form of thermal radiation, is another name for this type of radiation. The greater the temperature of the body, the more radiation of all wavelengths is emitted by it.

Relation of black body relation with Planck’s law

E = h ν


E = Energy of the radiation

h = Planck’s constant (6.626×10–34 J.s)

ν= Frequency of radiation

As a side note, Planck also found that these processes constituted just a small part of the whole. Nothing to do with the radiation’s physical actuality. Albert Einstein, a well-known German scientist, reworked Planck’s theory later in 1905 to explain the photoelectric effect in more detail. He believed that if a light source was done at certain materials, electrons may eject from the substance. As a result of Planck’s study, Einstein was able to determine that light existed as quanta of energy, or photons.

Postulated Planck’s Quantum Theory

  • Continuous radiation or emission of energy is not possible. Quanta, the term for the discrete packets of energy it emits, are the smallest units of its radiation.
  • A photon is the unit of measurement for a particle of radiation when it is in the form of light. In the case of light, photons are tiny energy particles.
  • The frequency of the radiation is exactly proportional to the energy of a photon or quantum of energy. Where h denotes Planck’s constant and v denotes radiation frequency, E = Hv.
  • There are a lot of ways to express the total energy of radiation, including h, 2h, and so on.

Evidence of Planck’s Quantum Theory

Planck’s quantum theory was the subject of several experiments. Quantum theory was backed up by a wealth of data from a wide range of experiments. Electron motion in the matter is quantized, according to all the evidence. Light may be split into wavelengths using a prism. Prisms produce rainbows only when light behaves as a wave. In addition, this lends credence to Max Planck’s quantum mechanics. Planck’s quantum theory of radiation is verified using the nitrogen gas emission spectra, as well.

FAQs on Planck’s Quantum Theory

Question 1: State some applications of Planck’s Quantum Theory.

Answer: In optical communications, lasers are done. The quantum nature of light causes the photons that make up the laser beam to be released into the atmosphere in distinct packets or quanta. Large volumes of data may be sent at rapid rates with this method.

Quantum computing is a further application of quantum theory. In a quantum computer, a qubit serves as the fundamental unit of information, and it may represent any integer between 0 and 1, including zero.

Question 2: Define Stefan’s Law of Radiation

Answer: The total radiant heat power output from a surface is proportional to its fourth absolute temperature power, according to Stefan law. Boltzmann’s rule only applies to black bodies, which are fictional surfaces that absorb heat radiation from all activities.

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