A 120-V rms signal at 60.0 Hz is applied across a 30.0-mH inductor and a 100-Ω resistor. What is the rms value of the voltage across the inductor?
A) 0.700 V
B) 119 V
C) 100 V
D) 13.5 V
E) 120 V

Question

Quizplus · Accepted Answer

The impedance of the circuit can be found using the formula:

Z = √(R^2 + XL^2)

where R is the resistance, XL is the inductive reactance, and Z is the impedance.

XL can be found using the formula:

XL = 2πfL

where f is the frequency and L is the inductance.

Substituting the given values, we get:

XL = 2π(60)(30×10^-3) = 11.3 Ω

Z = √(100^2 + 11.3^2) = 100.6 Ω

The rms current in the circuit can be found using Ohm's law:

I = Vrms/Z = (120/√2)/100.6 = 1.19 A

The voltage across the inductor can then be found using the formula:

VL = XLI = 11.3 × 1.19 = 13.5 V

Therefore, the answer is D.

A 120-V Rms Signal at 60