Alternating Current Circuits
Physics ⇒ Electricity and Magnetism
Alternating Current Circuits starts at 11 and continues till grade 12.
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Define the term 'impedance' in an AC circuit.
Describe the effect of increasing the resistance in a series RLC circuit on the sharpness of resonance.
Explain why alternating current is preferred over direct current for long-distance power transmission.
Explain why the power factor is important in AC circuits.
A 100 V, 60 Hz AC supply is connected to a 0.5 μF capacitor. Calculate the capacitive reactance.
A 100 Ω resistor, a 0.2 H inductor, and a 50 μF capacitor are connected in series to a 230 V, 50 Hz AC supply. Calculate the impedance of the circuit.
A 200 Ω resistor is connected to a 100 V, 50 Hz AC supply. Calculate the rms current through the resistor.
A 60 W, 120 V lamp is to be used on a 240 V, 50 Hz AC supply. What value of non-inductive resistance should be connected in series with the lamp?
In a purely resistive AC circuit, the current and voltage are:
(1) In phase
(2) Out of phase by 90°
(3) Out of phase by 180°
(4) Out of phase by 45°
The frequency of the AC mains supply in most countries is:
(1) 25 Hz
(2) 50 Hz
(3) 100 Hz
(4) 200 Hz
Which of the following devices is used to measure alternating current?
(1) Galvanometer
(2) Hot-wire ammeter
(3) Potentiometer
(4) Wheatstone bridge
Which of the following is NOT a characteristic of alternating current?
(1) It changes direction periodically
(2) It has a constant magnitude
(3) It can be represented by a sine wave
(4) It can be transformed using a transformer
In an AC circuit, the average power consumed is given by P = ______.
The angular frequency (ω) of an AC source with frequency f is given by ω = ______.
The average power consumed in a circuit with voltage V and current I having a phase difference φ is given by ______.
The impedance of a series RLC circuit is given by Z = ______.
True or False: In a series RLC circuit at resonance, the impedance is minimum.
True or False: The average power consumed in a purely inductive or capacitive AC circuit is zero.
True or False: The average value of a pure sinusoidal alternating current over a complete cycle is zero.
True or False: The average value of an AC voltage over half a cycle is 0.637 times its peak value.
