JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर JEE PYQ-Current Electricity Charging and Discharging of Capacitors

  • question_answer
    The length of a wire of a potentiometer is 100 cm and the emf of its stand and cell is. E volt. It is employed to measure the emf of a battery whose internal resistance is \[0.5\,\,\Omega \]. If the balance point is obtained at \[1=30\] cm from the positive end, the emf of the battery is               [AIEEE 2003]

    A) \[\frac{30\,E}{100.5}\]

    B) \[\frac{30\,E}{100-05}\]

    C) \[\frac{30\,(E-0.5i)}{100}\], where \[i\] is the current in the potentiometer wire                                   

    D) \[\frac{30\,E}{100}\]

    Correct Answer: D

    Solution :

    [d] Potential difference of wire
                            \[V\propto l\]
    \[\therefore \]      \[\frac{V}{E}=\frac{l}{L}\]
    where, \[l=\] length   of   balance   point   of potentiometer-wire
    L = length of potentiometer wire
    or         \[V=\frac{l}{L}E\]
                \[V=\frac{30\times E}{100}=\frac{30}{100}E\]


You need to login to perform this action.
You will be redirected in 3 sec spinner