Alternating Current

Physics · Chapter 11 · Units 3-4: Magnetic Effects of Current and Magnetism; Electromagnetic Induction and Alternating Currents

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Your path through this chapter

1
Visual lesson Beta
1. Part 1: AC values, reactance and the series LCR circuit20 slides
2. Part 2: Power, resonance and the AC generator20 slides
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Notes Beta
6 sections with key terms, formulas and exam tips.
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Flashcards Beta
30 cards for quick recall of key terms and facts.
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Practice
75 board-style questions with instant checks: Numerical 21, Short answer 18, Multiple choice 16, Assertion and reason 7.
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Chapter test Free
Short and long chapter tests in board pattern, with results and analysis.
- Chapter test (long) — Alternating Current · 40 marks · 100 min
- Chapter test (short) — Alternating Current · 20 marks · 50 min
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Sinusoidal alternating voltage and current; period, frequency and phase; mean and RMS values
AC through pure R, pure L and pure C: phase lead and lag, phasor diagrams; reactances X_L = omega L and X_C = 1/(omega C); graphs against frequency
Series LCR circuit: phasor method, impedance Z, phase angle; RL and RC special cases; graphs of Z and I against frequency
Power in AC circuits: average power, power factor cos(phi) = R/Z; wattless current; choke coil
Electrical resonance: f0 = 1/(2 pi sqrt(LC)); bandwidth and Q factor; LC oscillations
AC generator: principle, construction, theory and working; differences between AC and DC