(a)Find the wavelength of the radiation required to excited the electron is `Li^(++)` from the first to the third Bohr orbit (b) How many spectral lines are obseved in the emission spactrum of the above excited system?

Explanation

To solve the given problem, we will break it down into two parts as per the question.

### Part (a): Finding the Wavelength of Radiation

1. **Identify the Formula**:
We will use the formula for the wavelength of radiation emitted or absorbed during an electronic transition in a hydrogen-like atom:
\[
\frac{1}{\lambda} = RZ^2 \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right)
...