Construction Coordinator Practice Exam

What occurs when there is an impedance mismatch between the coaxial cable and the load?

1. All signal energy is absorbed by the load

2. All signal energy is reflected back to the source

3. Some signal energy is transferred to the load while some is reflected

4. No signal energy is affected

The correct answer is: Some signal energy is transferred to the load while some is reflected

When there is an impedance mismatch between the coaxial cable and the load, it leads to a scenario where some of the signal energy is transferred to the load while some is reflected back towards the source. This phenomenon occurs because the load does not present the ideal impedance that matches the coaxial cable’s characteristic impedance. In electrical engineering, when impedance is matched, maximum power transfer occurs, meaning all signal energy flows into the load. However, when there is a mismatch, a portion of the signal cannot continue down the transmission path and instead reflects back. The signal that does reach the load gets absorbed or utilized, while the remainder reflects towards the source. Thus, the correct answer encapsulates the reality of what happens in such mismatched situations, highlighting the duality of energy transfer and reflection that occurs. The other options do not accurately represent the effects of impedance mismatch. For instance, stating that all energy is absorbed implies perfect matching, while suggesting all energy is reflected ignores the fact that some energy is always transferred to the load. Lastly, claiming that no signal energy is affected contradicts the fundamental principles of signal behavior in the context of transmission lines and load interactions.