Which one among the following statements related to electric cells is <strong>CORRECT</strong>?

  1. A. A primary cell is rechargeable.
  2. B. A secondary cell can be used only once.
  3. C. The emf of a battery is the power provided by the battery per unit current.
  4. D. The unit of emf is Joule.

Correct Answer: C. The emf of a battery is the power provided by the battery per unit current.

Explanation

Electromotive force (emf) is mathematically defined as the power (P) supplied divided by the current (I), since P = V \times I. Thus, emf is the power provided by the battery per unit current.

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