Obtain an expression for the frequency of radiations emitted when a hydrogen atom de-excites from level n to level (n-1). for larger n, show that the frequency equals the classical frequency of revolution of the electron in the orbit.

Explanation

To solve the problem of obtaining an expression for the frequency of radiations emitted when a hydrogen atom de-excites from level \( n \) to level \( n-1 \), we will follow these steps:

### Step 1: Understand the Energy Levels
In a hydrogen atom, the energy levels are given by the formula:
\[ E_n = -\frac{13.6 \, \text{eV}}{n^2} \]
where \( n \) is the principal quantum number.
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