New York State Master Electrician Practice Exam

What is the total resistance of a circuit consisting of two 8MFD capacitors connected in series at 60HZ?

1. 440 ohms

2. 663 ohms

3. 800 ohms

4. 1000 ohms

The correct answer is: 663 ohms

To determine the total resistance of a circuit with capacitors, we need to calculate the capacitive reactance and understand the nature of the connection. Capacitors do not contribute resistance in the same way resistors do, but they do offer capacitive reactance, which can be treated as an opposition to current flow in AC circuits. The formula for the capacitive reactance (X_C) is given by: \[ X_C = \frac{1}{2\pi f C} \] Where: - \( f \) is the frequency in hertz (60 Hz in this case). - \( C \) is the capacitance in farads. For two capacitors in series, the total capacitance (C_total) can be derived using the formula for capacitors in series: \[ \frac{1}{C_{total}} = \frac{1}{C_1} + \frac{1}{C_2} \] Here, both capacitors have the same capacitance of 8 microfarads (MFD), or \( 8 \times 10^{-6} \) farads. The calculation for total capacitance would be: \[ \frac{1}{C_{