Question

An X-ray tube emits X-rays with a wavelength of 1.0 X 10^-11 m. Determine the energy, in electron volts, possessed by the incident electrons

Answer 1

Answer:

$1.25\cdot 10^5 eV$

Explanation:

The energy of the incident electron is equal to the energy acquired by the X-rays photon emitted by the tube, which is given by

$E=\frac{hc}{\lambda}$

where

h is the Planck constant

c is the speed of light

$\lambda$ is the wavelength

In this problem, the wavelength of the photon is

$\lambda=1.0\cdot 10^{-11} m$

Therefore, the energy is

$E=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{1.0\cdot 10^{-11} m}=2.0\cdot 10^{-14} J$

And keeping in mind that

$1 eV = 1.6\cdot 10^{-19} J$

We find the energy in electron volts:

$E=\frac{2.0\cdot 10^{-14}J}{1.6\cdot 10^{-19} J/eV}=1.25\cdot 10^5 eV$