Pennsylvania Esthetician State Board Practice Exam

What device contains two metal pieces that make contact with each other to allow electrical current flow?

1. Circuit Breaker

2. Transformer

3. Relay

4. Switch

The correct answer is: Circuit Breaker

The correct answer is a switch. A switch is designed to make or break an electrical connection by opening or closing a circuit, allowing or stopping the flow of electrical current. When the two metal pieces within a switch make contact, they complete the circuit, enabling current to flow. This fundamental component is critical in both simple and complex electrical systems, providing control over power distribution. A circuit breaker is a safety device that interrupts current flow when a fault is detected, but it operates differently than a standard switch; it's meant to disconnect the circuit under fault conditions rather than serve as a control mechanism for regular on-off operations. A transformer is used to change the voltage of an electrical supply, consisting of coils rather than metal pieces making contact. It functions on the principle of electromagnetic induction and does not directly control current flow in a circuit like a switch does. A relay is an electromagnetic switch that uses an electric current to open or close circuits. While it also involves contacts that can close and allow current flow, it operates through electromagnetic mechanisms, differing from the straightforward principle of a switch making contact manually. Therefore, the switch's primary function of opening and closing circuits to allow or prevent electrical current flow clearly identifies it as the answer to the question presented.