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A potentiometer circuit has been set up for finding the internal resistance of given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance, R, connected across the given cell, has values of.

(i).  Infinity

(ii). 9.5 \Omega

the 'balancing lengths', on the potentiometer wire are found to be 3 m and 2.85 m, respectively.

The value of internal resistance of the cell is:

  • Option 1)

    0.25 \Omega

  • Option 2)

    0.95 \Omega

  • Option 3)

    0.5 \Omega

  • Option 4)

    0.75 \Omega

 

Answers (1)

best_answer

r=\left ( \frac{l_{1}-l_{2}}{l_{2}}\right )R

   =\left ( \frac{3-2.85}{2.85}\right )\left ( 9.5 \right )

   r=0.5\Omega

 


Option 1)

0.25 \Omega

This option is incorrect

Option 2)

0.95 \Omega

This option is incorrect

Option 3)

0.5 \Omega

This option is correct

Option 4)

0.75 \Omega

This option is incorrect

Posted by

divya.saini

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