A voltage applied to an `X`-ray tube being increased `eta = 1.5` times, the short-wave limit of an `X`-ray continuous spectrum shifts by `Delta lambda = 26 p m`. Find the initial voltage applied to the tube.

Explanation

To find the initial voltage applied to the X-ray tube, we can follow these steps:

### Step 1: Understand the relationship between energy, wavelength, and voltage
The energy of a photon can be expressed as:
\[ E = \frac{hc}{\lambda} \]
where:
- \( E \) is the energy of the photon,
- \( h \) is Planck's constant (\( 6.626 \times 10^{-34} \, \text{Js} \)),
...