AFOQT Practice Test

What is the primary effect of a voltage source in an electric circuit?

1. It reduces the resistance

2. It powers the movement of electrons

3. It isolates the circuit

4. It generates static electricity

The correct answer is: It powers the movement of electrons

The primary effect of a voltage source in an electric circuit is to power the movement of electrons. A voltage source, such as a battery or a power supply, establishes an electrical potential difference between its terminals. This potential difference creates an electric field, which causes free electrons in conductors to move, thereby generating an electric current. When a voltage is applied across a circuit, the energy supplied by the voltage source is converted into kinetic energy for the electrons, allowing them to flow and perform work, such as lighting a bulb or powering a device. Therefore, the correct answer highlights the fundamental role of the voltage source in driving current through the circuit.