National Dental Assisting Examining Board (NDAEB) Practice Exam

What is the designation of the negative electrode inside the x-ray tube?

1. Anode

2. Cathode

3. Generator

4. Detector

The correct answer is: Cathode

The designation of the negative electrode inside the x-ray tube is the cathode. The cathode plays a crucial role in the x-ray production process. It consists of a filament, which is heated to produce electrons through thermionic emission. These electrons are then accelerated towards the anode, which is the positive electrode in the tube. The cathode's function is essential, as it generates the flow of electrons necessary for x-ray photons to be created when these electrons collide with the anode. Understanding the cathode's role emphasizes its importance in the x-ray beam’s generation and the overall functioning of the x-ray machine. In contrast to the cathode, the anode is the positive electrode where the electrons hit to produce x-rays. The generator refers to the equipment that produces the high voltage needed to propel the electrons from the cathode to the anode, and the detector is a device that captures the x-ray image. Each of these components has a distinct role, but the cathode is specifically identified as the negative electrode within the x-ray tube.