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

Options

A. 0.56
B. 0.64
C. 0.8
D. 0.33

Answer

C

Explanation

Power factor =cos`phi=(R)/(|Z|)=(8)/sqrt(8^(2)+(31-25)^(2)`
`(8)/sqrt(8^(2)+6^(2))=(8)/(10)=0.8`