Find wavelength of `1^(st)` line of Paschen series of hydrogen spectrum.

Explanation

To find the wavelength of the first line of the Paschen series of the hydrogen spectrum, we can follow these steps:

### Step-by-Step Solution

1. **Understand the Paschen Series**: The Paschen series corresponds to electronic transitions where the final energy level (n1) is 3. The first line of the Paschen series occurs when the electron transitions from n2 = 4 to n1 = 3.

2. **Use the Rydberg Formula**: The wavelength (λ) of the emitted light during these transitions can be calculated using the Rydberg formula:
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