NEET Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर NEET PYQ-Current Electricity Charging Capacitors

  • question_answer
    For a cell the terminal potential difference is \[2.2\text{ }V\] when circuit is open and reduces to \[1.8\text{ }V\] when cell is connected to a resistance \[R=5\,\Omega ,\] the internal resistance (r) of cell is:                       [AIPMT 2002]

    A)        \[\frac{10}{9}\Omega \]

    B)       \[\frac{9}{10}\,\Omega \]

    C)  \[\frac{11}{9}\Omega \]

    D)                   \[\frac{5}{9}\Omega \]

    Correct Answer: A

    Solution :

    [a] In an open circuit, emf of cell
                            \[E=2.2\text{ }V\]
                In a closed circuit, terminal potential difference
                            \[V=1.8\text{ }V\]
                External resistance, \[R=5\,\Omega \]
                Thus, internal resistance of cell is
                \[r=\left( \frac{E}{V}-1 \right)\,\,R=\left( \frac{2.2}{1.8}-1 \right)\,5\]
                \[=\left( \frac{11}{9}-1 \right)\,5=\frac{2}{9}\times 5=\frac{10}{9}\Omega \]


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