Ham Radio General Class Practice Test

What would be the RMS voltage across a 50-ohm dummy load dissipating 1200 watts?

1. 173 volts

2. 245 volts

3. 346 volts

4. 692 volts

The correct answer is: 245 volts

To find the RMS voltage across a 50-ohm dummy load that is dissipating 1200 watts, you can use the formula that relates power (P), resistance (R), and voltage (V). The formula is: \[ P = \frac{V^2}{R} \] Where: - \( P \) is the power in watts, - \( V \) is the RMS voltage in volts, - \( R \) is the resistance in ohms. To find the RMS voltage, rearrange the formula to solve for \( V \): \[ V = \sqrt{P \times R} \] Substituting the given values into the equation: \[ V = \sqrt{1200 \, \text{watts} \times 50 \, \text{ohms}} \] \[ V = \sqrt{60000} \] \[ V = 245 \, \text{volts} \] Thus, the RMS voltage across the dummy load is 245 volts. This calculation illustrates how power, resistance, and voltage are interrelated in electrical systems, particularly in the context of radio frequencies where accurate voltage measurements are essential for ensuring proper operation of equipment and preventing damage.