InterviewSolution
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InterviewSolution
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In an electrical circuit `R,L,C` and an `AC` voltage source are all connected in series. When `L` is removed from the circuit, the phase difference between the voltage and the current in the circuit is `pi//3`. If instead, `C` is removed from the circuit, difference the phase difference is again `pi//3`. The factor of the circuit isA. `1/2`B. `1/(sqrt(2))`C. `1`D. `(sqrt(3))/2` |
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Answer» Correct Answer - C We define phase difference, `tan phi=(X_(L)-X_(C))/R` When `L` is removed, `tan ((pi)/3)=sqrt(3)=(X_(C))/R` `implies X_(C)=sqrt(3)R` When `C` is removed, `tan(pi/3)=sqrt(3)=(X_(L))/R` `implies X_(L)=Rsqrt(3)` Hence, in resonant circuit, `tan phi=(X_(L)-X_(C))/R=0` `implies tan phi=(sqrt(3)R-sqrt(3)R)/R=0` `:.` Power factor `cos phi=1` |
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