Question

The electron beam in a colour TV is accelerated through 32 kV and then strikes the screen. What is the wavelength of the most energetic X-ray photon?

Answer 1

Given:
Potential of the electron beam, V = 32 kV = 32 × 10³ V
Energy, $E=32\times {10}^3\mathrm{eV}$
Wavelength of the X-ray photon $\left(\lambda \right)$ is given by
$\lambda =\frac{h\mathrm{c}}{E}$
Here,
h = Planck's constant
c = Speed of light
$$\begin{gathered} \therefore \lambda =\frac{hc}{E} \\ \Rightarrow \lambda =\frac{1242\mathrm{eVnm}}{32\times {10}^3} \\ \Rightarrow \lambda =38.8\times {10}^{-3}\mathrm{nm} \\ \Rightarrow \lambda =38.8\mathrm{pm} \end{gathered}$$