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 power factor of the circuit isA. `(1)/(2)`B. `(1)/(sqrt(2))`C. 1D. `(sqrt(3))/(2)` |
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Answer» Correct Answer - C When L is removed from the circuit, it becomes RC circuit. `tan phi = "tan" (pi)/(3)=(X_(C ))/(R ) therefore X_(C )=R "tan" (pi)/(3)=sqrt(3)R` When C is removed from the circuit, itbecomes RL circuit. `therefore tan phi = "tan"(pi)/(3)="tan"(pi)/(3)=(X_(L))/(R ), X_(L)=R "tan" (pi)/(3)=sqrt(3)R` Impedance of the circuit, `Z=sqrt(R^(2)+(X_(L)-X_(C ))^(2))=R` Power factor, `cos phi=(R )/(Z)=(R )/(R )=1`. |
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