A `12.5eV` electron beam is used to bombard gaseous hydrogen at room temperature. What serious of wavelength will be emitted?

Explanation

To solve the problem of finding the series of wavelengths emitted when a 12.5 eV electron beam bombards gaseous hydrogen, we can follow these steps:

### Step 1: Convert the energy from eV to joules
The energy of the electron beam is given as 12.5 eV. We need to convert this energy into joules using the conversion factor \(1 \text{ eV} = 1.6 \times 10^{-19} \text{ J}\).

\[ E = 12.5 \text{ eV} \times 1.6 \times 10^{-19} \text{ J/eV} = 2.0 \times 10^{-18} \text{ J} \]
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