**An alternating current of frequency ‘f’ is flowing in a circuit containing a resistance R and a choke L in series. … √[R2 + L2] …**

###### Answers:

The correct option (b) √[R^{2} + 4π^{2}f^{2}L^{2}]

Explanation:

Circuit is R – L series circuit, hence impedance

z = √[R^{2} + ω^{2}L^{2}]

z = √[R^{2} + (2πf)^{2}L^{2}]

z = √[R^{2} + 4π^{2}f^{2}L^{2}]