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MHT CET 2025 (23 Apr, Shift 2) · Potentiometer

Potentiometer question from MHT CET 2025 (23 Apr, Shift 2)

Q29MHT CET 2025 · 23 APR · SHIFT 2Medium

Potentiometer

The length of a potentiometer wire is ' LL '. A cell of e.m.f. ' EE ' is balanced at a length L4\frac{L}{4} from the positive end of the wire. If the length of the original wire is increased by L3\frac{\mathrm{L}}{3}, then using the same cell null point is obtained at

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Answer: (b)

  1. k=VLk = \dfrac{V}{L}, so E=VL⋅L4=V4E = \dfrac{V}{L}\cdot\dfrac{L}{4} = \dfrac{V}{4}.
  2. New length 4L3\dfrac{4L}{3}: 3V4L x=V4\dfrac{3V}{4L}\,x = \dfrac{V}{4}
  3. x=L3x = \dfrac{L}{3}
  4. So the answer is (b) L3\dfrac{L}{3}.
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