Goodmarks
Sign in

Physics · Internal resistance, potential difference and emf of a cell, a combination of cells in series and parallel

The figure shows a potentiometer arrangement. D is the driving cell. C is the ce

The figure shows a potentiometer arrangement. D is the driving cell. C is the cell whose emf is to be determined. AB is the potentiometer wire and \( G \) is a galvanometer.J is a sliding contact which can touch any point on AB. Which of the following are essential conditions for obtaining balance? This question has multiple correct options

  • A. The emf of D must be greater than the emf of \( C \).
  • B. Either the positive terminals of both D and C or the negative terminals of both \( D \) and \( C \) must be joined to \( A \)
  • C. The positive terminals of D and C must be joined to A.
  • D. The resistance of G must be less than the resistance of \( A B \)

Step-by-step solution

In a potentiometer, for balance, the driving cell D and the test cell C must be connected so that their emfs oppose the potential difference along the wire. This is achieved by connecting like terminals (both positive or both negative) to the same end A. Option A is also essential (emf of D > emf of C), but option B correctly captures the polarity condition without being overly restrictive, as option C is (which incorrectly insists on positive terminals only). Option D is irrelevant.
Practise more in this unitView MCQsSign up for full question bank

Related MCQs