CET Karnataka Medical CET - Karnataka Medical Solved Paper-2012

  • question_answer
    A resistor of, an inductance of 0.5 H are in series with an a.c. which is given by \[V=100\sqrt{2}\sin \](10000. The power factor of the combination is

    A)  \[\frac{1}{\sqrt{2}}\]   

    B)  \[\frac{1}{\sqrt{3}}\]  

    C)  \[0.5\]    

    D)  \[0.6\]

    Correct Answer: A

    Solution :

    : Here, \[R=500\Omega \],  \[L=0.5H\] Compare  \[V=100\sqrt{2}\sin (1000t)\]with \[V={{V}_{0}}\sin \omega t\] we get \[\omega =1000\] The inductive reactance is \[{{X}_{L}}=\omega L=(1000)(0.5)=500\Omega \] Impedance of the RL circuit is \[Z=\sqrt{{{R}^{2}}+X_{L}^{2}}=\sqrt{{{(500\Omega )}^{2}}+{{(500\Omega )}^{2}}}500\sqrt{2}\Omega \]Power factor, \[\cos \phi =\frac{R}{Z}=\frac{500\Omega }{500\sqrt{2}\Omega }=\frac{1}{\sqrt{2}}\]


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