Assume an electron with charge e and mass m is going around in a circular path of radius r around the nucleus of an atom having atomic number Z. If we define frequency f for this electron equal to the number of revolution per second, then calculate f.

Explanation

To calculate the frequency \( f \) of an electron revolving around the nucleus of an atom, we can follow these steps:

### Step 1: Understand the Forces Acting on the Electron
The electron with charge \( -e \) is moving in a circular path around the nucleus which has a charge of \( +Ze \) (where \( Z \) is the atomic number). The electron experiences a centripetal force due to the electrostatic attraction between the electron and the nucleus.

### Step 2: Apply Coulomb's Law
According to Coulomb's law, the electrostatic force \( F \) between the electron and the nucleus can be expressed as:
\[
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