JEE Main & Advanced Sample Paper JEE Main - Mock Test - 9

  • question_answer
    A sinusoidal voltage of amplitude 25 volt and frequency 50Hz is applied to a half wave rectifier using P-n junction diode. No filter is used and the load resistor is \[1000\Omega \]. The forward resistance \[{{R}_{f}}\]of ideal diode is\[10\Omega \]. The percentage rectifier efficiency is

    A) 40%  

    B) 20%    

    C) 30%             

    D) 15%

    Correct Answer: A

    Solution :

    \[{{I}_{m}}=\frac{{{V}_{m}}}{{{R}_{f}}+{{R}_{L}}}=\frac{25}{(10+1000)}=24.75\,mA\]
    \[{{I}_{dc}}=\frac{{{I}_{m}}}{\pi }=\frac{24.75}{3.14}=7.87\,mA\]
    \[{{I}_{rms}}=\frac{{{I}_{m}}}{2}=\frac{24.75}{2}=12.37\,mA\]
    \[{{P}_{dc}}={{I}_{dc}}^{2}\times {{R}_{L}}={{(7.87\times {{10}^{-3}})}^{2}}\times {{10}^{3}}=61.9\,mW\]
    \[{{P}_{ac}}={{I}_{rms}}^{2}({{R}_{f}}+{{R}_{L}})={{(12.37\times {{10}^{-3}})}^{2}}\times (10+1000)\]\[=154.54\,mW\]
    Rectifier efficiency \[\eta =\frac{{{P}_{dc}}}{{{P}_{ac}}}\times 100=\frac{61.9}{154.54}\times 100=40.05%\]


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