Class 12 · Chapter 7
Alternating Current
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Alternating Current Practice Questions
18 questions on Alternating Current. Try each one before checking the answer.
An alternating current has a peak value of 10 A. What is its average value over a half cycle?
An alternating current is given by I = 5√2 sin(100πt) A. What is its rms value?
A voltage V = V₀ sin(ωt + π/6) drives a current I = I₀ sin(ωt − π/6) in a circuit. By what phase angle does the current lag the voltage?
An inductor of inductance (1/π) H is connected to a 50 Hz AC supply. Calculate its inductive reactance.
A capacitor of capacitance (100/π) μF is connected to a 50 Hz AC source. Find its capacitive reactance.
In a series LR circuit, R = 30 Ω and X_L = 40 Ω. What is the impedance of the circuit?
In a series RC circuit, R = 10√3 Ω and X_C = 10 Ω. By what phase angle does the applied emf lag the current?
A series LCR circuit has R = 6 Ω, X_L = 18 Ω, and X_C = 10 Ω. Calculate the impedance of the circuit.
A series LCR circuit has L = 1 H and C = 1 μF. Calculate its resonant frequency.
A series LCR circuit with R = 50 Ω is driven at its resonant frequency by a 200 V (rms) source. What is the rms current in the circuit?
For a series LCR circuit with R = 10 Ω, L = 1 H and C = 1 μF, calculate the quality factor.
A series resonant circuit has a resonant frequency of 2000 Hz and a quality factor of 50. What is its bandwidth?
In an AC circuit, the resistance is 80 Ω and the total impedance is 100 Ω. What is the power factor?
An AC source with rms voltage 200 V drives an rms current of 2 A through a circuit, with the current lagging the voltage by 60°. Calculate the average power consumed.
The rms current in an AC circuit is 10 A, and the phase angle between voltage and current is 30°. What is the wattless component of the current?
An ideal choke coil (zero ohmic resistance) is connected to an AC source. What are its power factor and average power consumption?
An LC circuit has L = 10 mH and C = 1 μF, with the capacitor initially charged to 100 μC. What is the maximum current that flows in the circuit?
In a free LC oscillation of period T, the capacitor is fully charged at t = 0. At what minimum time is the energy shared equally between the capacitor and the inductor?
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