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  5. Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर

12th Class Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर Question Bank Case Based (MCQs) - Current Electricity

  • question_answer
    If external resistance connected to a cell has been increased to 5 times, the potential difference across the terminals of the cell increases from 10 V to 30 V. Then, the emf of the cell is :

    A) 30V

    B) 60 V

    C) 50 V

    D) 40 V

    Correct Answer: B

    Solution :

    For first case,\[\frac{\varepsilon }{R+r}=\frac{10}{R}\]           ... (i) or second case,\[\frac{\varepsilon }{5R+r}=\frac{30}{5R}\]                       … (ii) Dividing (i) by (ii), we get r = 5R From (i), \[\frac{E}{R+5R}=\frac{10}{R}\] E =60V


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