Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

In a series circuit, what happens if one load goes out?

1. Electrons continue to flow

2. The circuit remains closed

3. The circuit becomes open

4. Current increases in the circuit

The correct answer is: The circuit becomes open

In a series circuit, all components are connected along a single path, meaning that the current flows through each component sequentially. If one load, such as a light bulb or resistor, fails or is disconnected, it creates a break in the circuit path. This interruption prevents the flow of electric current throughout the entire series circuit. When the circuit becomes open because of the failure of one load, it means that there’s a discontinuity, and as a result, the other loads cannot receive electrical energy to operate. Thus, no current can flow through any part of the circuit, which is why the option indicating that the circuit becomes open is the accurate choice. In contrast, the other options suggest scenarios that cannot happen in a series circuit following the failure of one load.