JIPMER Jipmer Medical Solved Paper-2013

  • question_answer
    A uniform wire of resistance R and length L is cut into four equal parts, each of length L/4 which are then connected in parallel combination. The effective resistance of the combination will be

    A)  \[R\]                      

    B)         \[4R\]

    C)  \[\frac{R}{4}\]                 

    D)         \[\frac{R}{16}\]

    Correct Answer: D

    Solution :

    Resistance\[R=\frac{\rho l}{A}\] when wire cut into 4 equal parts, then    \[R'=\frac{\rho l}{A\cdot 4}=\frac{R}{4}\] Now, from parallel combination of resistor, \[\frac{1}{{{R}_{e{{q}^{u}}}}}=\frac{1}{\left( \frac{R}{4} \right)}+\frac{1}{\left( \frac{R}{4} \right)}+\frac{1}{\left( \frac{R}{4} \right)}+\frac{1}{\left( \frac{R}{4} \right)}=\frac{16}{R}\] \[\therefore \] \[{{R}_{e{{q}^{u}}}}=\frac{R}{16}.\]


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