BVP Medical BVP Medical Solved Paper-2002

  • question_answer
    A parallel plate capacitor with air as medium between the plates has a capacitance of 10\[\mu F\]. The area of capacitor is divided in two equal halves and filled with two media having dielectric constants \[{{k}_{1}}=2\] and \[{{k}_{2}}=4\]The capacitance of the system will now be :

    A)  40\[\mu F\]                      

    B)  30\[\mu F\]

    C)  10\[\mu F\]                      

    D) \[\frac{20}{3}\mu F\]    

    Correct Answer: D

    Solution :

                    Initial capacitance \[C=10\mu F\] \[\frac{{{\varepsilon }_{0}}A}{d}=10\mu F\] when it is filled with two different media then it will like a combination of two capacitors of capacitances \[{{C}_{1}}\] and \[{{C}_{2}}\] in series.                 \[{{C}_{1}}=\frac{{{K}_{1}}{{\varepsilon }_{0}}A/2}{d}\]                 \[=\frac{{{K}_{1}}}{2}\left( \frac{{{\varepsilon }_{0}}A}{d} \right)=\frac{2}{2}\times 10=10\mu F\]                 \[{{C}_{2}}=\frac{{{K}_{2}}}{2}\left( \frac{{{\varepsilon }_{0}}A}{d} \right)=\frac{4}{2}\times 10=20\mu F\] New capacity \[C=\frac{{{C}_{1}}{{C}_{2}}}{{{C}_{1}}+{{C}_{2}}}\]                 \[=\frac{10\times 20}{10+20}\]                 \[=\frac{200}{30}=\frac{20}{3}\mu F\]


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