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JCECE Medical JCECE Medical Solved Paper-2013

  • question_answer
    A coil is wound on a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor 2 and the number of turns per unit length of the coil remains the same, the self inductance increases by a factor of

    A)  4

    B)  8

    C)  12

    D)  16

    Correct Answer: B

    Solution :

     We have, self inductance, \[L=\frac{{{\mu }_{0}}{{n}^{2}}A}{l}\] Given, \[n/l\]is constant, doubling the length would double n also. Besides this, area would become four times on doubling linear dimensions. So,      \[\frac{{{L}_{2}}}{{{L}_{1}}}=\frac{n_{2}^{2}}{n_{1}^{2}}.\frac{{{A}_{2}}}{{{A}_{1}}}\times \frac{{{l}_{1}}}{{{l}_{2}}}\] Here,    \[\frac{{{L}_{2}}}{{{L}_{1}}}=4\times 4\times \frac{1}{2}=8\] \[\Rightarrow \] \[{{L}_{2}}=8{{L}_{1}}\]


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