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Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectric Current in Conductors

Two nonideal batteries are wired in parallel. Evaluate the following statements: (A) The equivalent emf is smaller than either of the individual emfs. (B) The equivalent internal resistance is smaller than either of the individual internal resistances.

Options

  1. AA is correct but B is incorrect
  2. BB is correct but A is incorrect
  3. CBoth A and B are correct
  4. DBoth A and B are incorrect

Correct answer

B. B is correct but A is incorrect

Step-by-step solution

For two batteries connected in parallel with emfs E₁ and E₂ and internal resistances r₁ and r₂ , the equivalent emf is given by E_ eq = E₁ r₂ + E₂ r₁ r₁ + r₂ . This expression shows that E_ eq is a weighted average of E₁ and E₂ . Thus, E_ eq always lies between E₁ and E₂ and cannot be smaller than both individual emfs. Hence, statement A is incorrect. The equivalent internal resistance is given by the parallel combination of the individual internal resistances, r_ eq = r₁ r₂ r₁ + r₂ . In a parallel combination of r

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