= Three impedances Z = 3-j4 ohm, Z2 = 6+j14 ohm and Z3 5 ohm are connected in series across a 240V (r.m.s.), 50Hz single-phase AC supply. Calculate (a) the r.m.s. magnitude and phase angle of circuit current with respect to supply voltage, (b) power factor of the whole circuit (mention lag or lead) and (c) the value of capacitance to be connected across the supply so that the circuit now operates at unity power factor and the circuit current with the capacitance connected. [4+2+6=12]