Alternating Current & RMS — A/L Physics

How do I practise Alternating Current & RMS?

1 question with a worked solution

1. A sinusoidal alternating voltage is given by v(t) = 311 sin(100π t) V. What are the root-mean-square (RMS) voltage V_rms and the frequency f of this alternating supply?
   1. A) V_rms = 220 V, f = 50 Hz
   2. B) V_rms = 311 V, f = 100 Hz
   3. C) V_rms = 220 V, f = 100 Hz
   4. D) V_rms = 155 V, f = 50 Hz
   Check my answer

   Correct answer: A) V_rms = 220 V, f = 50 Hz

   Standard equation: v(t) = V₀ sin(2π f t). Peak voltage V₀ = 311 V. V_rms = V₀ / √2 = 311 / 1.414 ≈ 220 V. Angular frequency ω = 2π f = 100π => f = 50 Hz.

   Show worked solution

   Step 1: V_rms = V₀ / √2 = 311 / 1.414 = 220 V. Step 2: ω = 2π f = 100π => f = 50 Hz. Answer: V_rms = 220 V, f = 50 Hz.
   Modelled on: the A/L Physics examination pattern

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Where does Alternating Current & RMS fit in the syllabus?

Unit 8.4 · Year 2 · Term 1