(a) (i) Mention the factors on which the resonant frequency of a series LCR circuit depends. Plot a graph showing variation of impedance of a series LCR circuit with the frequency of the applied a.c. source. (ii) With the help of a suitable diagram, explain the working of a step-up transformer. (iii) Write two causes of energy loss in a real transformer. OR (b) (i) With the help of a diagram, briefly explain the construction and working of ac generator. (ii) An electron is revolving around a proton in an orbit of radius r with a speed v. Obtain expression for magnetic moment associated with the electron.