Direct and Alternating Current
Physics ⇒ Electricity and Magnetism
Direct and Alternating Current starts at 9 and continues till grade 12.
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See sample questions for grade 12
A 100 Ω resistor is connected to a 220 V, 50 Hz AC supply. Calculate the RMS current through the resistor.
A 100 Ω resistor is connected to an AC source with a peak voltage of 141 V. What is the RMS voltage across the resistor?
A 12 V battery supplies a current of 2 A for 3 hours. How much electrical energy is delivered in kilowatt-hours (kWh)?
A 230 V, 50 Hz AC supply is connected to a lamp. What is the time period of the AC waveform?
A 60 W, 120 V lamp is connected to a 120 V DC supply. What is the current through the lamp?
A generator produces an AC voltage described by V(t) = 100 sin(314t) V. What is the frequency of the AC voltage?
A resistor of 10 Ω is connected to a 12 V DC supply. Calculate the current flowing through the resistor.
A sinusoidal AC has a maximum value of 10 V. What is its RMS value?
Define the term 'root mean square (RMS) value' in the context of alternating current.
Describe one advantage and one disadvantage of using AC over DC.
Describe the function of a rectifier in an electrical circuit.
Explain the main difference between direct current (DC) and alternating current (AC).
Explain why AC is preferred over DC for long-distance power transmission.
Explain why household electrical appliances are usually designed to operate on AC rather than DC.
The root mean square (RMS) value of an AC current is 5 A. What is its peak value? (Assume a sinusoidal waveform)
