A 10Ω electric heater is connected to a 220V 50Hz mains supply. What is the peak value of the potential difference across the heater element ?
Correct answer: D. 220 √2V
- A. 220V
- B. 220/ 2V
- C. 110V
- D. 220 √2V
Explanation
The 220 V mains value is an RMS voltage. For a sinusoidal supply, Vpeak = √2 Vrms = √2 x 220 V = 220√2 V, approximately 311 V. Students may choose a by treating the quoted mains voltage as the peak value instead of the RMS value.
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About AC Through Resistor, Capacitor and Inductor
Alternating current through a resistor, capacitor and inductor involves phase relationships between voltage and current, reactance, impedance and energy transfer. A resistor keeps voltage and current in phase, while a capacitor and inductor produce opposite phase shifts, a distinction used in circuit diagrams and numerical calculations.
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