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

Capacitors in AC Circuits

Physics

31. Alternating Current

Capacitors in AC Circuits

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Multiple Choice

A 300 µF capacitor is connected to an AC source operating at an RMS voltage of 120 V. If the maximum current in the circuit is 1.5 A, what is the oscillation frequency of the AC source?

29.4 Hz

4.68 Hz

41.7 Hz

6.63 Hz

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Verified step by step guidance

Start by understanding the relationship between the maximum current (I_max), the RMS voltage (V_rms), and the capacitive reactance (X_c) in an AC circuit. The formula for capacitive reactance is X_c = 1 / (2πfC), where f is the frequency and C is the capacitance.

Use the formula for the maximum current in an AC circuit: I_max = V_max / X_c. Note that V_max (maximum voltage) is related to V_rms by the equation V_max = V_rms * √2.

Substitute V_max = V_rms * √2 into the equation for I_max, giving I_max = (V_rms * √2) / X_c.

Rearrange the equation to solve for X_c: X_c = (V_rms * √2) / I_max.

Substitute X_c = 1 / (2πfC) into the equation and solve for the frequency f: f = 1 / (2πC * X_c). Use the given values: C = 300 µF (or 300 x 10^-6 F), V_rms = 120 V, and I_max = 1.5 A, to find the frequency.