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COMEDK2020PhysicsCurrent Electricity

To the potentiometer wire of length L and 10 resistance, a battery of emf 2.5 ~V and a resistance R are connected in series. If a potential difference of 1 ~V is balanced across L / 2 length, the value of R in will be

Options

  1. A1
  2. B1.5
  3. C2
  4. D2.5

Correct answer

D. 2.5

Step-by-step solution

The given situation is shown below. Resistance of potentioneter wire, R_ p =10 BmI, E=25 ~V Total resistance, R^ =R_ p +R=(10+R) Current through potentiometer wire, l= E R_ p = 25 10+R Since, potential difference across length A L= L ~g , aligned & V &=l ( R_ g 2 ) & & 1 &= 25 10+R 10 2 & 10+n &=125 & & R &=25 aligned

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