A coil of inductive reactance 31 Ω has a resistance of 8 Ω. It is placed in series with a condenser of capacitive reactance 25 Ω. The combination is connected to an AC source of 110 V. The power factor of the circuit is

power factor (cosϕ) is a ratio of resistance and impedance of AC circuit.Power factor of AC circuit is given bycosϕ=RZ                           …(i)Z=R2+XL−XC2         ….(ii)Equations (i) and (ii) give,cosϕ=RR2+XL−XC2   …(iii)Given, R=8 Ω, XL=31 Ω, XC=25 Ωcosϕ=8(8)2+(31−25)2=864+36cosϕ=0.80