Chapter 31 - Electromagnetic Oscillations and Alternating Current - Problems - Page 939: 68a

$\phi = 1.22~rad$

We can find the phase constant: $tan~\phi = \frac{X_L-X_C}{R}$ $tan~\phi = \frac{\omega_d~L-1/\omega_d~C}{R}$ $tan~\phi = \frac{2\pi~f~L-1/2\pi~f~C}{R}$ $tan~\phi = \frac{(2\pi)~(2000~Hz)~(60.0\times 10^{-3}~H)-1/(2\pi)~(2000~Hz)~(0.400\times 10^{-6}~F)}{200~\Omega}$ $tan~\phi = 2.775193$ $\phi = tan^{-1}~(2.775193)$ $\phi = 1.22~rad$