A resistance R and an inductance L are connected in series in an a.c. circut. If `omega` is the angular frequency of the source, then the power factor is given by

Options

A. `(omega L)/(R)`
B. `(R)/(omega L)`
C. `(R)/(sqrt(R^(2)+omega^(2) L^(2)))`
D. `(R)/(sqrt(R^(2)-omega^(2) L^(2)))`

Answer

C

Explanation

`tan theta = (omega L)/R`
`:.` Power factor = `cos theta = (R)/(sqrt(R^(2)+L^(2)omega^(2)))`