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⚛️ Physics  ·  Current Electricity  ·  NEET & JEE

For a long potentiometer wire, balance point is at 40 cm for a standard cell of 1.02 V. EMF of another cell balancing at 50 cm:

Answer: 1.275 V.

  • A 0.82 V
  • B 1.02 V
  • C 1.275 V
  • D 2.04 V

Correct answer: C. 1.275 V

Explanation: EMF is proportional to balance length. E<sub>2</sub>/E<sub>1</sub> = l2/l1. E<sub>2</sub> = 1.02 x 50/40 = 1.275 V.

SeriesbatteryR1R2I (same in R1, R2)ParallelbatteryR1R2I1I2

In series, the same current flows through both resistors; in parallel, the current splits between branches and the voltage across each resistor is the same.

Concept context

Ohm's law, resistors, Kirchhoff's laws, Wheatstone bridge, and cells.

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