What is the velocity of electron in Bohr's third orbit of hydrogen atom ? Also calculate the number of revolutions the electron makes in Bohr's third orbit in one second.

Explanation

To find the velocity of an electron in Bohr's third orbit of a hydrogen atom and the number of revolutions it makes in one second, we can follow these steps:

### Step 1: Calculate the Velocity of the Electron in the Third Orbit

The formula for the velocity \( v_n \) of an electron in the \( n \)-th orbit of a hydrogen atom is given by:

\[
v_n = \frac{e^2}{2 \epsilon_0 h} \cdot \frac{1}{n}
...