1. **Problem Statement:** Determine which statement best describes an AC signal's RMS voltage value. 2. **Understanding RMS Voltage:** RMS (Root Mean Square) voltage is a measure of the effective value of a varying AC voltage. It represents the equivalent DC voltage that would deliver the same power to a load. 3. **Formula for RMS Voltage:** For a sinusoidal AC voltage with peak value $V_{peak}$, the RMS voltage $V_{rms}$ is given by: $$V_{rms} = \frac{V_{peak}}{\sqrt{2}}$$ 4. **Explanation of Options:** - Option 1: "It is always equal to the peak value" is incorrect because RMS is less than the peak value. - Option 2: "It is always equal to the peak-to-peak value" is incorrect because peak-to-peak is twice the peak value, which is larger than RMS. - Option 3: "It is the constant value that would deliver the same average power as a DC signal of the same value" is correct because RMS voltage corresponds to the DC equivalent power. - Option 4: "It is calculated as twice the peak value" is incorrect; RMS is not twice the peak. 5. **Final Answer:** The best description is option 3. **Answer:** 3. It is the constant value that would deliver the same average power as a DC signal of the same value.