Question: 38. A circuit is at resonance when:
a) I LINE lags E SOURCE
b) R is zero
c) X L equals X C
d) R is less than Z
39. One of the bushings on a capacitor bank has been tracking and that tank must be changed. Which of the following statements are correct?
a) Isolate the bank, wait five minutes, install EPZ and proceed with your work.
b) Isolate the bank, install EPZ, wait five minutes and go to work.
c) Isolate the bank, wait five minutes and go to work.
d) Isolate the bank and proceed with your work.
40. When you are reading current with a clip-on amp meter, the value that your reading is:
a) the maximum value
b) the effective or RMS value
c) the peak value
d) the average value
41. Find the voltage drop across the inductive reactance in Figure 4.
Figure 4: series circuit diagram with a 22,000 V source on the left, an inductor at the top labeled X L = 190Ω, a resistor on the right labeled R = 20Ω, and a capacitor at the bottom labeled X C = 160Ω.
1. **Problem statement:** Find the voltage drop across the inductive reactance $X_L$ in the given series circuit with source voltage $V_s = 22000$ V, inductive reactance $X_L = 190\ \Omega$, resistance $R = 20\ \Omega$, and capacitive reactance $X_C = 160\ \Omega$.
2. **Formula and rules:** In a series RLC circuit, the total impedance $Z$ is given by:
$$Z = \sqrt{R^2 + (X_L - X_C)^2}$$
The current $I$ in the circuit is:
$$I = \frac{V_s}{Z}$$
The voltage drop across the inductive reactance is:
$$V_{X_L} = I \times X_L$$
3. **Calculate total impedance $Z$:**
$$Z = \sqrt{20^2 + (190 - 160)^2} = \sqrt{400 + 30^2} = \sqrt{400 + 900} = \sqrt{1300}$$
$$Z = 36.06\ \Omega$$
4. **Calculate current $I$:**
$$I = \frac{22000}{36.06} = 610.1\ \text{A}$$
5. **Calculate voltage drop across $X_L$:**
$$V_{X_L} = 610.1 \times 190 = 115919\ \text{V}$$
6. **Answer:** The voltage drop across the inductive reactance $X_L$ is approximately $115919$ volts.