Four graphs I–IV show how induced emf varies with time for different generators. Which graph(s) may represent an alternating emf? [Image]
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Four graphs I–IV show how induced emf varies with time for different generators. Which graph(s) may represent an alternating emf? [Image]

G1 Physics · Accepted Answer

Step 1: An alternating-current generator creates an induced emf as magnetic flux through rotating coils changes. Step 2: Periodic emf alternates polarity, so its graph should take positive and negative values in an alternating pattern. Step 3: Among the supplied four graph types, each alternating positive/negative waveform is AC; printed answer C includes (I),(II),(III),(IV). Final answer: (C) (I), (II), (III) and (IV).