Which statement is true about the x-ray tube anode?

• A. It is the negative electrode.
• B. It is the positive electrode.
• C. It is the source of electrons.
• D. It is the glass envelope that encloses the tube.

Answer: (B)

The key idea is that the anode acts as the positive electrode in the x-ray tube. The cathode (negative electrode) emits electrons when heated, and those electrons are accelerated toward the anode by the high-voltage potential. When the fast electrons strike the anode’s target, X-rays are produced. So the anode is the positive terminal and the target where X-rays originate. It’s not the source of electrons—that’s the cathode—and it’s not the glass envelope, which simply houses the tube components. The anode’s design (often a rotating tungsten target) helps dissipate the heat generated by the electron impacts.