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JEE Main 2023 (1 Feb, Shift 1) · Potentiometer

Potentiometer question from JEE Main 2023 (1 Feb, Shift 1)

Q38JEE Main 2023 · 1 FEB · SHIFT 1Easy

Potentiometer

In an experiment to find emf of a cell using potentiometer, the length of null point for a cell of emf 1.5 V1.5\text{ V} is found to be 60 cm60\text{ cm}. If this cell is replaced by another cell of emf E, the length-of null point increases by 40 cm40\text{ cm}. The value of EE is x10 V\frac{x}{10}\text{ V}. The value of xx is ____________.

Numerical answer type. Work it out, then open the answer.

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Answer: 25

  1. E∝lE \propto l, new length =60+40=100 cm= 60 + 40 = 100\ \text{cm}.
  2. E=1.5×10060=2.5 V=2510 VE = 1.5 \times \frac{100}{60} = 2.5\ \text{V} = \frac{25}{10}\ \text{V}.
  3. So x=25x = 25.
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