NEET Sample Paper NEET Sample Test Paper-81

  • question_answer
    An alternating current is given by\[\operatorname{I}={{I}_{1}}\ cos\,\,\omega t\,\,+\,\,{{I}_{2}}\,sin\,\,\omega t\]. The root mean square current is given by

    A)  \[\frac{{{\left( {{I}_{1}}+{{I}_{2}} \right)}^{2}}}{2}\]                       

    B)  \[\frac{\left( {{I}_{1}}+{{I}_{2}} \right)}{\sqrt{2}}\]

    C)  \[\sqrt{\frac{\left( I_{1}^{2}+I_{2}^{2} \right)}{2}}\]              

    D)  \[\frac{\sqrt{I_{1}^{2}-I_{2}^{2}}}{2}\]

    Correct Answer: C

    Solution :

    As, \[I={{I}_{1}}\cos \,\omega t+{{I}_{2}}\sin \,\,\omega t\] \[\therefore  \,\,Resultant current, {{I}_{0}} = \sqrt{I_{1}^{2}\,\,+\,\,I_{2}^{2}}\] Hence, the rms current form relation is given by \[{{I}_{rms}}=\frac{{{Z}_{0}}}{\sqrt{2}}=\frac{\sqrt{I_{1}^{2}+I_{2}^{2}}}{\sqrt{2}}\,\,=\,\,\sqrt{\frac{\,I_{1}^{2}+I_{2}^{2}}{2}}\]


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