Table of contents

0. Math Review31m
- Math Review
  31m
1. Intro to Physics Units1h 29m
2. 1D Motion / Kinematics3h 56m
3. Vectors2h 43m
4. 2D Kinematics1h 42m
5. Projectile Motion3h 6m
6. Intro to Forces (Dynamics)3h 22m
7. Friction, Inclines, Systems2h 44m
8. Centripetal Forces & Gravitation7h 26m
9. Work & Energy1h 59m
10. Conservation of Energy2h 54m
11. Momentum & Impulse3h 40m
12. Rotational Kinematics2h 59m
13. Rotational Inertia & Energy7h 4m
14. Torque & Rotational Dynamics2h 5m
15. Rotational Equilibrium3h 39m
16. Angular Momentum3h 6m
17. Periodic Motion2h 9m
18. Waves & Sound3h 40m
19. Fluid Mechanics4h 27m
20. Heat and Temperature3h 7m
21. Kinetic Theory of Ideal Gases1h 50m
22. The First Law of Thermodynamics1h 26m
23. The Second Law of Thermodynamics3h 11m
24. Electric Force & Field; Gauss' Law3h 42m
25. Electric Potential1h 51m
26. Capacitors & Dielectrics2h 2m
27. Resistors & DC Circuits3h 8m
28. Magnetic Fields and Forces2h 23m
29. Sources of Magnetic Field2h 30m
30. Induction and Inductance3h 38m
31. Alternating Current2h 37m
32. Electromagnetic Waves2h 14m
33. Geometric Optics2h 57m
34. Wave Optics1h 15m
35. Special Relativity2h 10m

31. Alternating Current

Impedance in AC Circuits

Physics

31. Alternating Current

Impedance in AC Circuits

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Multiple Choice

An AC source operates at a maximum voltage of 120 V and an angular frequency of 377 s^-1 . If this source is connected in parallel to a 15 Ω resistor and in parallel to a 0.20 mF capacitor, answer the following questions:
a) What is the maximum current produced by the source?
b) What is the maximum current through the resistor?
c) What is the maximum current through the capacitor?

a) 12 V b) 8A c) 4A

a) 12 V b) 8A c) 9A

a) 7.8 V b) 7.6A c) 0.2A

a) 8.9 V b) 8A c) 4A

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Verified step by step guidance

To find the maximum current produced by the source, we need to calculate the total impedance of the parallel circuit. The impedance of the resistor (R) is 15 Ω, and the impedance of the capacitor (Z_C) can be calculated using the formula Z_C = 1 / (ωC), where ω is the angular frequency (377 s⁻¹) and C is the capacitance (0.20 mF).

Calculate the capacitive reactance (X_C) using the formula X_C = 1 / (ωC). Substitute ω = 377 s⁻¹ and C = 0.20 mF (which is 0.20 x 10⁻³ F) into the formula to find X_C.

The total impedance (Z_total) of the parallel circuit can be found using the formula for parallel impedances: 1/Z_total = 1/R + 1/X_C. Calculate Z_total using the values of R and X_C obtained in the previous steps.

The maximum current produced by the source (I_max) can be calculated using Ohm's Law for AC circuits: I_max = V_max / Z_total, where V_max is the maximum voltage of the source (120 V).

To find the maximum current through the resistor (I_R) and the capacitor (I_C), use Ohm's Law for each component: I_R = V_max / R and I_C = V_max / X_C, respectively. Calculate these currents using the given values.