What is the maximum DC or RMS voltage that may be connected across a 20 watt, 2000 ohm resistor?

Get ready for the FCC General Radiotelephone Operator License (GROL) exam. Study with flashcards and multiple choice questions, each with hints and detailed explanations. Prepare effectively for your licensing test!

Multiple Choice

What is the maximum DC or RMS voltage that may be connected across a 20 watt, 2000 ohm resistor?

The amount of heat a resistor dissipates is P = V^2 / R, so the maximum voltage it can handle without exceeding its 20 W rating is V = sqrt(P × R). With P = 20 W and R = 2000 Ω, V = sqrt(20 × 2000) = sqrt(40,000) = 200 V. This applies to both DC and RMS AC voltages, since RMS voltage determines the heating effect. So the highest DC or RMS voltage allowed is 200 volts; higher voltages would push the power beyond the 20 W rating (for example, 10 V yields 0.05 W, 100 V yields 5 W, and 10,000 V would yield 50,000 W).

The amount of heat a resistor dissipates is P = V^2 / R, so the maximum voltage it can handle without exceeding its 20 W rating is V = sqrt(P × R). With P = 20 W and R = 2000 Ω, V = sqrt(20 × 2000) = sqrt(40,000) = 200 V. This applies to both DC and RMS AC voltages, since RMS voltage determines the heating effect. So the highest DC or RMS voltage allowed is 200 volts; higher voltages would push the power beyond the 20 W rating (for example, 10 V yields 0.05 W, 100 V yields 5 W, and 10,000 V would yield 50,000 W).

More practice questions