The power factor of a circuit containing a lamp of resistance 100 `Omega`, a choke coil of inductance 0.2 H and a condenser of capacitance 1 mH connec
The power factor of a circuit containing a lamp of resistance 100 `Omega`, a choke coil of inductance 0.2 H and a condenser of capacitance 1 mH connected in series with an alternating emf of frequency 50 Hz is
A. 1.86
B. 86.6
C. 8.66
D. 0.86
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Correct Answer - D
`X_(L)=2pifL=2xx3.14xx50xx1xx0.2`
`=62.8kOmega`
`X_(C)=(1)/(2pifC)=(1)/(2xx3.14xx50xx1xx10^(-6))`
`=3.185Omega`
Power factor `=cosphi=(R)/(Z)`
`=(R)/(sqrt(R^(2)+(X_(L)-X_(C))^(2)))`
`=(100)/(sqrt(100^(2)+(62.8-3.185)^(2)))`
`=0.859~~0.86`
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