Q.

To an AC power supply of 220 V at 50 Hz, a resistor of 20Ω, a capacitor of reactance 25Ω, and an inductor of reactance 45Ω  are connected in series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively           [2025]
 

1 15.6 A and 30°  
2 15.6 A and 45°  
3 7.8 A and 30°  
4 7.8 A and 45°  

Ans.

(4)

Given, V=220 V, υ=50 Hz

R=20Ω,  XL=45Ω,  XC=25Ω

Current, I=VZ=220R2+(XL-XC)2=220400+400=220202=112=7.8A

Phase angle, ϕ=tan-1(XL-XCR)=tan-1(45-2520)=tan-1(2020)

ϕ=45°