Planck’s Constant is one of the smallest constants used in physics. It is a fundamental constant in quantum mechanics which relates the energy of a photon to its frequency. Planck constant stands as one of the most elegant and pivotal values in the realm of physics, where constants shape the very essence of this physical world.
Further in this article, we will learn about its definition, who Max Planck was, explore methods for calculating its value in various units, its formula, dimension, and unit. We will look into what’s a Reduced Planck Constant and discuss the application of Planck’s constant across various scientific disciplines.
.webp)
What is Planck Constant?
Planck’s constant, symbolized as ℎ, is a fundamental universal constant that defines the quantum nature of energy and relates the energy of a photon to its frequency, now known as the Planck-Einstein relation:
E = ℎf
Where,
- E represents the energy of the light,
- f is the frequency of the light, and
- ℎ is referred to as the Planck constant.
Planck Constant tells us that energy exchanged at the quantum level occurs in some specific amount, known as quanta. The Planck’s constant says how much of that energy is in these quanta. One quanta is defined by the value of the Planck’s Constant value (we will learn about this value later in this article.)
Discovery of Planck Constant
German physicist Max Planck introduced the constant in 1900 when he was working on a formula to describe the distribution of radiation emitted by a blackbody, also known as blackbody radiation. This constant, now known as Planck’s constant, was crucial in resolving a problem known as the ultraviolet catastrophe, a point where classical physics failed to explain the observed physics.
Who is Max Planck?
Max Planck was a German physicist who pioneered the field of quantum theory. Planck’s most famous contribution was quantization of energy packets, which gave birth to the revolutionary idea that energy is not emitted or absorbed continuously but in discrete quantities. This constant came to be known as Planck’s constant and is now denoted by the symbol ‘ℎ’.
Value of Planck’s Constant
Planck’s constant, symbolized as ℎ, is a fundamental universal constant. From the data, its value is calculated and it came to be
6.62607015 × 10−34 Joule seconds
Value of Planck’s Constant in eV
Its value when calculated in terms of electron volts (eV) is very useful for quantum level calculations.
4.135667696 × 10−15 eV seconds
Its value can be easily calculated by putting values in the Planck-Einstein relation for the Photoelectric effect energy:
E = ℎf
Where E is the energy of the light, and f is the known frequency of the light.
Unit of Planck Constant
Planck’s constant is a very small value can be written in two formats:
Planck Constant = 6.62607015 × 10−34 Joule seconds
Here, 10-34 is a very small value, which is 1 in its 34th digit.
Planck Constant = 4.135667696 × 10−15 eV seconds
Here, 10-15 is a slightly larger but equivalently smaller quantity, which is 1 in its 15th digit.
Planck Constant Dimensions Formula
Dimension of Planck Constant is [ML2T-1]
Experimental Determination of Planck’s Constant
Experimental determination of Planck’s constant is done by the photoelectric effect. In this experiment, the energy of the electron emitted from a metal surface is precisely measured when light strikes it.
Also measuring the frequency of the incident light, a direct relationship can be found between the energy of the photons and the frequency of the light, that’s Planck’s constant. Accuracy of these experiments perfectly validate Max Planck’s theory, and in turns strengthening our understanding of the quantum world.
Reduced Planck Constant
Frequency is measured using hertz. A 360° cycle or one full Bohr introduced the quantity ℏ = ℎ/2π , Its value is 1.054571817×10−34 joule seconds, known as the reduced Planck constant, represents the quantum of angular momentum and more commonly used in modern physics.
Application of Planck’s Constant Different Fields
Planck’s constant plays a unique and foundational role across various scientific fields. Here’s a few perspectives that highlights its distinct and direct contributions:
In Quantum Mechanics, Planck’s constant (ℎ) acts as a bridge between the macroscopic and microscopic worlds, defining the granularity of energy at the quantum level. It’s the fundamental quantum unit that underpins numerous phenomena, making it unparalleled in its significance.
Planck’s Constant in Different Fields
There are various uses of Planck’s Costant in different fields of physics, some of these applicationa are listed as follows:
Formula for spectral radiance B(v, T) is revolutionary, describing how objects emit light at different temperatures, and it is given by,
B(v, T) = 2ℎv3⁄c2 × 1 ⁄[eℎv/KT -1]
Planck-Einstein relation revolutionized our understanding of light’s interaction with matter, and it is given by,
E = ℎf
Within atomic models, Planck’s constant appears in equations describing the energy levels of electrons in orbits around the nucleus, and it is given by,
En = -ℎc0R∞ ⁄ n2
The uncertainty principle embodies a fundamental limitation in measuring both the position and momentum of a particle simultaneously, and it is given by,
ΔxΔp ≥ ℏ⁄ 2
The de Broglie wavelength equation relates a particle’s momentum to its associated wavelength, and it is given by,
λ= ℎ⁄p
Read More,
Planck’s Constant FAQs
What is Planck’s Constant?
Planck’s constant, denoted as ℎ, is a fundamental constant in quantum mechanics that relates the amount of energy carried by photon to its frequency.
What is Planck’s Length, and What’s its Relation to Planck’s Constant?
Theoretically it is believed that Planck’s length is the smallest measurable length in the known universe, its value is roughly 1.616×10-35 meters, derived from Planck’s constant.
Can Planck’s Constant importance be Experimentally Demonstrated?
Yes, the Photoelectric effect effectively demonstrates the importance of Planck’s constant.
What is the Value of Planck’s Constant?
Its value is approximately 6.626×10−34 joule-seconds.
What is the Dimension of Planck’s Constant?
Dimension of Planck’s Constant is [ML2T-1].
What is the SI unit for Planck’s Constant?
SI unit of Planck’s Constant is Joule second.
What is Planck’s Constant in eV?
Value of Planck’s Contant is 4.135667696×10−15 eV seconds.
What is Reduced Planck Constant?
The reduced planks constant is ℏ=ℎ/2π.
Share your thoughts in the comments
Please Login to comment...