Cathodic Protection Tester Practice Exam

In a circuit with alternating current, what kind of frequency is typically observed?

1. Once a second

2. 50 or 60 times per second

3. 100 or 120 times per second

4. Constant frequency

The correct answer is: 100 or 120 times per second

In circuits utilizing alternating current (AC), the standard frequencies commonly observed are 50 Hz or 60 Hz, which correspond to 50 cycles per second or 60 cycles per second, respectively. These frequencies are the norm for power systems used in most countries, with 60 Hz being predominant in the Americas and 50 Hz in many parts of Europe and Asia. Option C indicates frequencies of 100 Hz or 120 Hz, which are not standard for power distribution systems. Instead, 100 Hz and 120 Hz do not align with consistently used AC frequencies in household or industrial settings. The reference to constant frequency implies a uniformity in the system, which aligns with alternating currents; they typically maintain a steady frequency unless influenced by specific changes in the power supply or generator control systems. Therefore, focusing on 50 or 60 Hz as the fundamental characteristic reinforces the understanding of alternating current.