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The variation of EMF with time for four types of generators are shown in the figures. Which amongst them can be called AC?

1. Only (a)
2. (a) and (b)
3. (a), (b), (c), (d)
4. (a) and (b)

Correct answer: (a) and (b)

Solution

AC (Alternating Current) is characterized by an EMF that alternates in direction over time. Graphs (a) and (b) show such alternating behavior, while others do not.

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