A capacitor and a resistor are connected in series with an a.c. source. If the potential difference across C, R are 120 V and 90 V repectively, and if rms value of current is 3 A, calculate impedance and power factor of the circuit.

Options

A. `5 // sqrt(2) Omega`
B. `4 Omega`
C. `5 Omega`
D. `4 sqrt(2) Omega`

Answer

C

Explanation

`V_(rms) = sqrt(V_(R)^(2) + (V_(L) - V_(C))^(2)) = sqrt(40^(2) + (40 - 10)^(2))`
`= sqrt(40^(2)+ 30^(2)) = 50 ` Volt
`Z = (V_(rms))/( I_(rms)) = (50)/(((10 sqrt(2))/(sqrt(2))))=(50)/(10) = 5 Omega `