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MHT CET20255 May 2025Evening ShiftPhysicsCurrent ElectricityActual

A 2.5 V battery is connected to a potentiometer wire. A cell of e.m.f. 1.08 V is balanced by the voltage drop across 2.16 m of wire. The length of the potentiometer wire is

Options

  1. A2.5 m
  2. B3 m
  3. C5 m
  4. D6 m

Correct answer

C. 5 m

Step-by-step solution

Potential gradient determination The known cell with E = 1.08 V balances at length l = 2.16 m , establishing the potential gradient k = E/l . k = 1.08 2.16 = 0.5 V/m Total wire length calculation The battery voltage V = 2.5 V equals the potential drop across the entire wire length L : V = kL . 2.5 = 0.5L L = 2.5 0.5 = 5 m The potentiometer wire length is C

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