Question

The value of Planck's constant is
A.${\text{6}}{{.6256 \times 1}}{{\text{0}}^{{\text{ - 27}}}}\,\,{\text{erg}}\,\,{\text{sec}}$
B.${\text{66}}{{.256 \times 1}}{{\text{0}}^{{\text{ - 27}}}}\,{\text{erg}}\,{\text{sec}}$
C.${\text{6}}{{.02 \times 1}}{{\text{0}}^{{\text{ - 15}}}}\,{\text{erg}}\,{\text{sec}}$
D.${\text{3}}{t{.01 \times 1}}{{\text{0}}^{{\text{ - 23}}}}\,{\text{erg}}\,{\text{sec}}$

Answer 1

Hint:Planck's constant (${\text{h}}$) is a fundamental physical constant , which is characteristic of the mathematical formulation of quantum mechanics. Planck's constant was discovered by German physicist Dr. Max Planck 1n 1900.The constant plays a crucial part of quantum mechanics , a branch of physics which deals with the tiny particles .

Complete answer:
Planck's constant relates energy in one quantum( photon) of an electromagnetic radiation to the frequency of that radiation. Which is given by the equation
${{E = h\nu }}$
Planck's constant defines the amount of energy that a photon can carry, according to the frequency of the wave in which it travels.
 The discovery of the Planck's constant is generally regarded as the starting point of quantum physics. Planck's constant ${\text{h}}$ is regarded as the universal constant.
In 1901 Max Planck s proposed Quantum theory ,the foundation of Planck's quantum theory is the theory of blackbody radiation.
A black body is defined as the ideal system or an object which absorbs and emits all the electromagnetic radiations incident on it. The electromagnetic radiation emitted by such black body is called black body radiation. Electromagnetic radiation is a form of energy which has both wave-like and particle like properties.
According to Planck's quantum theory
Energy is not emitted or absorbed continuously , it is emitted or absorbed in discrete quantities in the form of electromagnetic radiation known as quantum.in the case of light the quantum of energy is called a photon.
The amount of energy emitted or absorbed is directly proportional to the frequency of radiation, which is given by the equation
\[{\text{E}}\, \propto \nu \]
\[{\text{E}}\,{{ = }}\,{{h\nu }}\]
Where ${\text{h}}$ is the Planck's constant. A universal constant which is equal to the energy of a quantum of electromagnetic radiation when it is divided by its frequency. The value of ${\text{h}}$ is experimentally validated and is given by ${\text{6}}{{.6256 \times 1}}{{\text{0}}^{{\text{ - 27}}}}\,{\text{erg}}\,{\text{sec}}$ if the value is in C.G.S units.

Hence, here the correct answer is option A.

Note:
According to Planck's quantum theory the smallest amount of energy emitted or absorbed in the form of electromagnetic radiation is known as quantum, for light the quantum of energy also called photon. This photons travel at the speed of light in a vacuum , also this photons are required to explain the photoelectric effect and to explain particle nature of light