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The terminal potential difference of a battery is equal to its electromotive force (e.m.f.). whenits internal resistance become

Correct answer: B. zero.

  • A. low.
  • B. zero.
  • C. high.
  • D. constant.

Explanation

The terminal potential difference (V) of a battery is given by the formula \(V=E-Ir\), where E is the electromotive force (e.m.f.), I is the current flowing through the circuit, and r is the internal resistance of the battery. If the internal resistance (r) is zero, then the term \(Ir\) becomes zero. Therefore, \(V=E-0\), which simplifies to \(V=E\). This means that when the internal resistance is zero, the terminal potential difference is equal to the electromotive force. Answer: B) zero.

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About Internal Resistance of Sources

Internal resistance is the opposition to current inside a cell or other source, causing terminal voltage to fall below its emf when current flows. Questions use E = V + Ir, current in complete circuits, lost volts, source combinations, and the difference between internal resistance and the external load resistance.

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