What Are X-Rays?

Wilhelm Roentgen, a German scientist discovered in the year 1875, X-rays. These rays are also called Roentgen rays. Similar to light rays these are penetrating rays. They differ from light rays in the length of their waves and in their energy. The shortest wavelength from an X-ray tube may be one fifteen-thousandth to one-millionth of the wavelength of green height. X-rays can pass through materials because of the short wavelength which the light will not pass through. The shorter the wavelength, the more penetrating the waves become.

X-rays are produced in an X-Ray tube. The air is pumped from this tube until less than one hundred-millionth of the original amount is left. These tubes are normally glass tubes, with two electrodes. The one carrying a negative charge is called “the Cath-ode”. The tungsten coil inside it on heating by electric current gives off electrons. The other electrode is called the target or anode. The speed at which they travel is very great because of the difference. The strike speed at target varies from 96,000 to 280,000 kilometers per second.

The target either a block or a wheel of tungsten stops the electrons suddenly. Most of the electron energy is changed into heat. But part of it X-radiates and emerges from the bottom window in the shape of X-rays.

X-ray “picture” is a shadowgraph and is taken of bones in our body. These pass through the part of the body under X-ray and cast shadows on the film. The film is coated on both sides by an emulsion that is sensitive. After exposure, the film is developed like other photographic films. The bones cast denser shadows and are shown in light areas on the film as the X-rays do not penetrate them.

X-rays play a very important part in science, medicine, and industry and are a great helpful tool to man.