12. In an RLC series circuits, \(v_R(t)\), \(v_L(t)\), \(v_C(t)\) are the potential difference across a resistor and an inductor. What are the relation of \(v_R(t)\) in relation of \(i(t)\) and \(v_L(t)\) with \(i(t)\)?      (13)      (Hint: in phase; leads by 90°; lags by 90°)