2. Solved Papers
  3. Punjab Medical

Punjab Medical Punjab - MET Solved Paper-2007

  • question_answer
    A cell of emf\[X\]is connected across a resistor R. The potential difference across the wire is measured as V. The internal resistance of the cell should be

    A) \[X\text{--}Y/R\]                             

    B) \[(X-Y)R/Y\]

    C) \[(X-Y)Y/R\]                       

    D) \[(X-Y)R\]

    Correct Answer: B

    Solution :

    If \[r\] be the internal resistance of the cell, then the current through the circuit is given by                 \[l=\frac{E}{(R+r)}\] Substituting\[E=X\], we get                 \[I=\frac{X}{R+r}\]                                           ? (i) Now, potential difference across the resistor is given by                 \[V=IR\] Substituting\[V=Y,\,\,I=\frac{X}{R+r}\]     [from Eq. (i)] we get                 \[Y=\frac{XR}{R+r}\] On solving, we get                 \[r=\frac{(X-Y)R}{Y}\]


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