For a series RLC circuit R = XL = 2XC. The impedance of the circuit and phase difference (between) V and i will be
5R2, tan−1(2)
5R2,tan−112
5XC,tan−1(2)
5R, tan−112
XL=R, XC=R/2
∴tanφ=XL−XCR=R−R2R=12
⇒φ=tan−1(1/2)
Also Z=R2+(XL−XC)2=R2+R24=52R