NEIEP Mechanics Practice Exam

What is the primary function of CEMF in an electrical circuit?

1. Limits current flow

2. Enhances voltage

3. Increases resistance

4. Reduces inductance

The correct answer is: Limits current flow

The primary function of Counter Electromotive Force (CEMF) in an electrical circuit is to limit the current flow. CEMF is generated in inductive components, such as coils or transformers, when there is a change in current. According to Lenz's Law, CEMF acts in a direction that opposes the change in current that produced it. This opposition leads to a reduction in the overall current in the circuit, thereby regulating and controlling the flow of electricity. Understanding the role of CEMF is crucial in circuits that include inductors, as it plays a significant part in determining how these components react to varying current conditions. This phenomenon is also critical in understanding the behavior of electric motors, where CEMF increases as the motor speeds up, effectively limiting the current drawn from the power supply and preventing overheating or damage. By recognizing that CEMF serves to limit current flow, one can grasp its importance in maintaining proper functionality and safety within electrical circuits.