Assertion : At resonance, L C R series circuit have a minimum...

At resonance X_L=X_C or $\omega L=\frac{1}{\omega C}$. Because of this impedance of $L C R$ series circuit become equal to resistance of circuit \left(Z=\sqrt{R^2+\left(X_L-X_C\right)^2}\right)$. Therefore from$I=$\frac{E}{Z}=\frac{E}{R}$, at resonance, current in LCR series circuit is maximum. Correspondingly phase angle is also equal to zero. Therefore emf and current are in phase in L C R series circuit.