JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर Question Bank Different Measuring Instruments

  • question_answer
    Potentiometer wire of length 1 m is connected in series with 490\[\Omega \] resistance and 2V battery. If 0.2 mV/cm is the potential gradient, then resistance of the potentiometer wire is                                                   [DCE 2005]

    A)         4.9\[\Omega \]           

    B)         7.9\[\Omega \]

    C)  5.9\[\Omega \]               

    D)  6.9\[\Omega \]

    Correct Answer: A

    Solution :

                                             Potential gradient \[x=\frac{e}{(R+{{R}_{h}}+r)}.\frac{R}{L}\] Þ \[\frac{0.2\times {{10}^{-3}}}{{{10}^{-2}}}=\frac{2}{(R+490+0)}\times \frac{R}{1}\] Þ R = 4.9 W. 


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