What is the definition of current in a circuit?

Current in a circuit is defined as the flow of electricity, specifically the flow of electric charge, typically carried by electrons in a conductor. This flow is measured in amperes (A), and it is crucial for the operation of electrical devices and systems. Current indicates how many electrons are passing through a point in the circuit per unit of time.

Understanding this concept is fundamental because it allows one to analyze how electricity moves through circuits, affecting everything from the performance of electronic devices to the safety and efficiency of electrical installations. The other choices relate to different aspects of electrical theory: voltage pertains to electrical potential difference, resistance determines how much "push" is needed to move current through a circuit, and power refers to the rate at which energy is consumed. Each plays a vital role in circuit design and analysis, but none captures the essence of current as the movement of electric charge.