A series LR circuit is connected to an ac source of frequency $\omega$ and the inductive reactance is equal to $2R$. A capacitance of capacitive reactance equal to $R$ is added in series with $L$ and $R$. The ratio of the new power factor to the old one is:\\
(1) $\sqrt { \frac { 2 } { 3 } }$\\
(2) $\sqrt { \frac { 2 } { 5 } }$\\
(3) $\sqrt { \frac { 3 } { 2 } }$\\
(4) $\sqrt { \frac { 5 } { 2 } }$