InterviewSolution
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InterviewSolution
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In the circuit shown if fig, the rims currents `(I_1), (I_2)` and` (I_3)` are altered by varying the freqency f of the oscillator. The output voltage of the oscillatro remains sinusoidal and has a fixed amplitude. When curves in figure correctly indicate the variation with frequency of the currents `(I_1), (I_2),and (I_3)`. A. (A)`(I_1)=Q`, `(I_2)=Q`, `(I_3)=Q`B. (B)`(I_1)=R`, `(I_2)=Q`, `(I_3)=Q`C. (C) `(I_1)=Q`, `(I_2)=P`, `(I_3)=R`D. (D)`(I_1)=Q`, `(I_2)=R`, `(I_3)=P` |
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Answer» Correct Answer - D Rectancae of the inductor O is given by `X_(L)=2 pi f L`. Therefore, rms current through inductor L is `(I_2)` `=(V)/(2 pi f L) prop (1)/(f)` where V is the rms of the supply voltage . Reactance of the capacitor C is given by `(X_C)=(1)/(2 pi f C)` therefore, rms current through the capacitor is `(I_3)=(V)/(X_C) = 2 pi f CV prop f` The total current `(I_1)` is given by `(I_1)=(I_2)+(I_3)` `((V)/( 2 pi f L)- 2 pi f CV)` thus, `(I_2)` is best represented by curve R. `(I_3)` is best represented by curve P. `(I_1)` is best represented by curve Q. |
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