Question

Question #9b844

Answer 1

Energy and frequency for electromagnetic radiation are linked through the Planck relation, `E=hnu`

Explanation:

In his analysis of blackbody radiation, Max Planck came upon the relation between the energy and frequency of electromagnetic radiation:

`E=hnu`

where `nu` is the frequency, and `h` is Planck's constant.

This means that the higher the frequency of the radiation, the greater the amount of energy it carries with it. Low frequency must also imply low energy.

When an atom emits light in the form of a photon, the energy of the photon determines what the frequency the photon will have (and what portion of the spectrum it occupies).

Planck's constant will take on different numerical values, depending on the units used in a problem, but in units consistent with kJ/mol, its value is `3.99 xx 10^(-13)` kJ s/mol. It is one of the fundamental constants in the quantum mechanical world.

Once you have `h`, you calculate the frequency as follows:

`nu=E/h = (5.72xx10^5 "kJ/mol")/(3.99xx10^(-13) "kJ s/mol")= 1.43xx10^(18) Hz`