91Ó°ÊÓ

The frequency of a sinusoidal wave is the number of full oscillations performed by any wave component in one unit of time. The concept of frequency can be used to understand that if a body is in periodic motion, it has finished one cycle after going through a sequence of experiences or locations and returning to its initial state. As a result, frequency is a term used to indicate how frequently oscillations and vibrations take place.

The value of Planck's constant is–

\(h = 6.626 \times {10^{ - 34}}Js\)

And the speed of light is –

\(c = 3.00 \times {10^8}\;m\;{s^{ - 1}}\)

Therefore, it can be obtained –

\(\begin{aligned}hc = 6.626 \times {10^{ - 34}}Js \times 3.00 \times {10^8}\;m\;{s^{ - 1}}\\ = 1.9878 \times {10^{ - 25}}\;J\;m\end{aligned}\)

It is known that –

\(1.00\;m = {10^9}\;nm\)and,

\(1.00\;J = 6.242 \times {10^{18}}eV\)

Hence, it is obtained that –

­\(\begin{aligned}hc = 1.9878 \times {10^{ - 25}}Js \times \dfrac{{6.242 \times {{10}^{18}}eV}}{{1.00\;J}} \times \dfrac{{{{10}^9}\;nm}}{{1.00\;m}}\\ = 1240eV \cdot nm\end{aligned}\)

Therefore, it is proved that \(hc = 1240eV \cdot nm\).