Question

What is the unit of Planck’s Constant?

Answer 1

When a light beam contacts a surface, one of three effects can occur: reflection, refraction, or absorption. When it hits a typical surface, the majority of the light is absorbed. Mirrors are polished surfaces that have been coated with mercury to reflect the majority of the light that falls on them. Mirrors can now be classified as concave, convex, or planar mirrors based on their reflecting surface. We shall just discuss the plane mirror in this section. So, to generate a picture, at least two rays from the object must meet or appear to meet at a spot. In the instance of a plane mirror, three pictures were chosen for clarity in the ray diagram shown below.

Complete step by step solution:
The German Physicist Max Planck introduced the constant in 1900 in his accurate formulation of the distribution of the radiation emitted by a black body.
Planck’s Constant is basically used in quantum physics, whose symbol is denoted by $h$ and value is $6.626 \times {10^{ - 34}}\,Js$ .It has the units of action i.e. energy multiplied with time as well as angular momentum.
Hence in SI units the Planck’s Constant is expressed in $Js$ or $Nms$ or $kg\,{m^2}\,{s^{ - 1}}$.
Dimension of Planck’s Constant $\left[ {M{L^2}{T^{ - 1}}} \right]$ .
The derivation of Planck’s constant, $h$,involved combining this idea of quantum levels of energy with three recently developed concepts:
The Stephen-Boltzmann Law
Wien's Displacement Law
The Rayleigh-James Law
This led Planck Produce the relationship
$\Delta E = hv$
Where
$\Delta E$ is change in energy
$v$ is the particle’s oscillation frequency
This is known as the Planck’s Einstein equation, and the value of $h$.
Unit of Planck’s Constant is defined as follows:
$\left( 1 \right)\,h = Et$
Hence the SI unit will be $Js\,\,or\,\,kg{m^2}{s^{ - 1}}$ .
$\left( 2 \right)E = hv$
By rearranging the above equation
$h = \dfrac{E}{v}$
Hence the SI unit will be $J\,Hz$.

Note: Planck’s Constant is not only used in Planck’s Photoelectric equation but it has so many uses in quantum physics. It can be represented by different SI units but all are interrelated so don’t get confused.