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NTSE Sample Paper NTSE SAT Practice Test-15

  • question_answer
    n identical cells, each of emf E and internal resistance r, are joined in series to form a closed circuit. The potential difference across any one of the cells is:

    A) Zero                             

    B) E

    C) \[\frac{E}{n}\]                          

    D) \[\left( \frac{n-1}{n} \right)E\]

    Correct Answer: A

    Solution :

    [a] The equivalent circuit of any one of the cells is given by, \[{{V}_{A}}-{{V}_{B}}=-E+Ir\] But \[I=\frac{nE}{nr}\]             \[=\frac{E}{r}\] \[\therefore \,\,{{V}_{A}}-{{V}_{B}}=-E+\frac{E}{r}\times r\] \[=-\,E+E\] =0 So, potential difference across any one of the cells is zero.


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