The instantaneous AC emf is e = E₀ sin(ωt) and the current is i = I₀ sin(ωt - φ). What is the average power over one full cycle?
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The instantaneous AC emf is e = E₀ sin(ωt) and the current is i = I₀ sin(ωt − φ). What is the average power over one full cycle?

G1 Physics · Accepted Answer

Step 1: Write e=E₀sinωt and i=I₀sin(ωt−φ). Step 2: Instantaneous power p=e i=E₀I₀sinωt sin(ωt−φ). Use sinA sinB=(cos(A−B)−cos(A+B))/2. Step 3: Average second cosine over a complete cycle is zero, so ⟨p⟩=(E₀I₀/2)cosφ. Correct C. Final answer: (C) (E₀I₀/2) cosφ.