In a potentiometer circuit a cell of EMF 1.5 V gives balance point at 36 cm length of wire. If another cell of EMF 2.5 V replaces the first cell, then - Physics MCQ NEET 2021 2026 | ExamTest.live

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In a potentiometer circuit a cell of EMF 1.5 V gives balance point at 36 cm length of wire. If another cell of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs?

Solution & Step-by-step Explanation

In a potentiometer, the EMF E is proportional to the balancing length l : E \propto l \Rightarrow \frac{E _{1}}{E _{2}} = \frac{l _{1}}{l _{2}} Given E_{1} = 1.5 V, l_{1} = 36 cm, and E_{2} = 2.5 V . \frac{1.5}{2.5} = \frac{36}{l _{2}} l_{2} = \frac{2.5 \times 36}{1.5} l_{2} = \frac{5 \times 36}{3} = 5 \times 12 = 60 cm

Try it yourself before checking the explanation above.

In a potentiometer circuit a cell of EMF 1.5 V gives balance point at 36 cm length of wire. If another cell of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs?

64 cm

62 cm

60 cm

21.6 cm

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