Continuous X-ray - Practice Questions & MCQ

Continuous X-ray-

As we know about the phenomenon of visible light, similarly continuous $X$ ray spectra also contain photons ranging through a lot of wavelengths. From the previous concept, we know that the production of X-rays happens when the target which is made up of an element with a high atomic number is hit by electrons traveling at a high velocity. So out of the total energy, most of the energy applied is wasted by being converted into heat energy in the target material's system. X-rays that have continuously unstable wavelengths are produced due to the loss of energy that the few electrons who were moving fast enough (and penetrated to the interior sections of the atoms of the material being targeted) suffer. Since the attractive pulling forces applied by the nucleus of the target element cause a deceleration of these fast-moving electrons, this makes decreases the energy of the electron continuously. Due to this, varying frequency of X-rays is emitted continuously due to the retardation of the speed of electrons. The $X$ - rays consist of a continuous range of frequencies up to a maximum frequency $\nu_{\max }$ or minimum wavelength $\lambda_{\min }$. This is called continuous X - rays. The minimum wavelength depends on the anode voltage. If $V$ is the potential difference between the anode and the cathode, then -

$$
e V=h \nu_{\max }=\frac{h c}{\lambda_{\min }}
$$

To produce the continuous X-ray in the Coolidge tube, an electron is projected toward the anode with an accelerating voltage V. So, the kinetic energy of the projectile electron will be eV. As shown in the figure, it experiences strong electric force toward the nucleus of the atom and due to this strong attraction the velocity of this electron, when it emerges from the atom, will be highly reduced and negligible compared with the initial speed of the projectile electron.

According to the law of conservation of energy, the energy of these electromagnetic radiations will be equal to the decrease in the kinetic energy of the projectile electron.

$$
\begin{aligned}
& e V=\frac{1}{2} m v^2 \\
& v=\sqrt{\frac{2 e V}{m}}
\end{aligned}
$$

But the velocity of the incoming electron will be less as compared to the projectile electron. This difference in kinetic energy will cause the production of X-rays.