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

Explanation

To find 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 \(1 eV = 1.6 \times 10^{-19} J\).

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