Alternating Current Circuits
Physics ⇒ Electricity and Magnetism
Alternating Current Circuits starts at 11 and continues till grade 12.
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See sample questions for grade 12
A 100 Ω resistor, a 0.5 H inductor, and a 10 μF capacitor are connected in series to a 220 V, 50 Hz AC supply. Calculate the impedance of the circuit.
A 60 W, 120 V lamp is to be used on a 240 V, 50 Hz AC supply. What value of resistance should be connected in series with the lamp?
A coil of inductance 0.2 H and resistance 20 Ω is connected to a 220 V, 50 Hz AC supply. Calculate the inductive reactance.
A transformer has 500 turns in the primary and 100 turns in the secondary. If the input voltage is 220 V, what is the output voltage?
Explain why a transformer cannot work with direct current (DC).
If the current in an AC circuit is given by I = I₀ sin(ωt + φ), what does φ represent?
If the frequency of the AC supply is doubled, what happens to the capacitive reactance?
If the peak voltage of an AC source is 325 V, what is its rms value? (Give your answer to the nearest integer.)
State one practical application of resonance in AC circuits.
State the condition for resonance in a series LCR circuit.
The frequency of the AC supply in most countries is 50 Hz. What is the time period of one cycle?
The instantaneous value of an alternating current is given by I = 10 sin(100πt). What is the frequency of the current?
