ASNT Industrial Radiography Radiation Safety Practice Test

What is X-radiation primarily created by?

1. Applying high voltage alternating current across a cathode

2. Applying high voltage direct current across the cathode of a vacuum tube

3. Generating thermal energy within the tube

4. Applying static electricity to the target

The correct answer is: Applying high voltage direct current across the cathode of a vacuum tube

X-radiation is primarily generated by applying high voltage direct current across the cathode of a vacuum tube. In this process, a high voltage is applied, which accelerates electrons released from the cathode toward a target material, typically made of tungsten or another heavy metal. When these high-energy electrons collide with the target, they lose energy in the form of electromagnetic radiation, which is emitted as X-rays. This method is fundamental in industrial radiography as it allows for the creation of the penetrating radiation needed to inspect materials and components for internal flaws or structural integrity. The efficiency of X-ray production is enhanced through this method, making it the preferred technique.