What does a cathode represent in electrical terms?

In electrical terms, a cathode is defined as a negatively charged electrode. This is particularly relevant in various contexts, such as in electrolysis and in devices like batteries or vacuum tubes. When a circuit is completed, electrons flow toward the cathode, as it has a surplus of negative charge compared to the anode, which is the positively charged electrode. Understanding the role of a cathode is crucial for grasping the basics of electrical flow, as it indicates the direction of electron movement in a circuit.

The other options relate to concepts that either describe different types of electrodes or do not fit the definition of a cathode. For example, a positively charged electrode is referred to as an anode, while insulators impede electric current rather than facilitating it, and electromagnetic radiation pertains to wave phenomena rather than static electrical charge. Therefore, the definition of a cathode as a negatively charged electrode is fundamental in the study of electricity and electrochemical processes.