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NEET Sample Paper NEET Sample Test Paper-48

  • question_answer
    In a potentiometer of one metre length, an unknown emf voltage source is balanced at 60cm length of potentiometer wire, while a 3V battery is balanced at 45cm length. Then, the emf of the unknown voltage source is:

    A) 3V                   

    B) 2.25V  

    C) 4V                   

    D) 4.5V

    Correct Answer: C

    Solution :

    \[\operatorname{emf} \propto  balanced length\] \[{{\operatorname{E}}_{1}}-k{{\ell }_{1}}\]                               ...(1) \[{{\operatorname{E}}_{2}}-k{{\ell }_{2}}\]                   ...(2) \[{{\operatorname{E}}_{1}}=E,~{{E}_{2}}=3V\] \[{{\ell }_{1}}=60,~{{\ell }_{2}}=45\] \[\frac{E}{3}=\frac{k\times 60}{k\times 45}\] \[\operatorname{E} = 4V\]


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