Question

Velocity of X-rays are
$\begin{align}
  & \text{A}\text{. 3}\times \text{1}{{\text{0}}^{6}}mts/s \\
 & \text{B}\text{. 3}\times \text{1}{{\text{0}}^{5}}mts/s \\
 & \text{C}\text{. 3}\times \text{1}{{\text{0}}^{8}}mts/s \\
 & \text{D}\text{. none of these} \\
\end{align}$

Answer 1

Hint: X-rays rays are a type of very high energy electromagnetic wave. They have a very high frequency and low wavelength. All electromagnetic waves have the same velocity which is a universal constant i.e. the velocity of light.

Complete step-by-step answer:
The X-rays or the X-radiation is an electromagnetic radiation with very high energy. It has a very low wavelength in the range of ten picometres to ten nanometres i.e. ${{10}^{-12}}m-{{10}^{-9}}m$ . The frequency range of X-ray is $3\times {{10}^{15}}Hz$ to $3\times {{10}^{19}}Hz$.
From the frequency range and the wavelength range of the X-ray, we can find its energy range as 124 eV to 124 KeV.
The speed of light in vacuum is denoted by c, which is a universal physical constant. The approximate value of c is $3\times {{10}^{8}}m{{s}^{-1}}$. All the electromagnetic waves are light waves and the speed of all types of electromagnetic rays are same as the speed of light which is $3\times {{10}^{8}}m{{s}^{-1}}$.
X-ray is also a type of electromagnetic ray which has very high energy. So, we can say that X-ray or X-radiation is a light wave and the velocity of X-ray is also same as that of velocity of light i.e. $3\times {{10}^{8}}m{{s}^{-1}}$.
The correct option is (C).

Note:X-ray is used to detect bone fractures, tumours, cancer cells etc in the human body. The X-ray can pass through the tissue of or body but cannot pass through the bone. We can use a lead apron or lead shield to protect some parts of our body from X-ray. This is because the X-ray cannot penetrate the lead shield.