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PLEASE NOTE: IF YOU HAVE THE OPINION THAT INSUFFICIENT INFORMATION IS SUPPLIED FOR YOU TO ANSWER A PARTICULAR QUESTION, MAKE A REALISTIC ASSUMPTION, MOTIVATE IT AND THEN ANSWER THE QUESTION. QUESTION 1 1.1 Give a detailed discussion of breakdown phenomenon in commercial liquids. (10) 1.2 Which factor affect the breakdown of a liquid? (2) 1.3 Discuss three chemical reactions undergone by some dielectric material in the presence of air and other gases. 1.4 A coaxial cylindrical capacitor is to be designed with an effective length of 10cm. The capacitor is expected to have the capacitance of 100pF and to operate at 11kV. 1000kHz. Determine the required thickness if the required insulating material is Polytetrafluoroethylene (P.T.F.E.), r=2.7,Eb=132kV/cm. Allow a factor of safety of 3 and take 0=8.851012F/m while Emax =33kV/cm. QUESTION 2 2.1 Describe briefly with the aid of suitable diagrams, one form of electrostatic generators used in generating high dc voltages. (6) 2.3 A Van-de-Graaf generator produces 1000N force on its belt. A variable speed motor drive is driving the generator directly. The diameter of the pulley on the motor side of the generator is 20cm. If the input power of the motor is 1.5kW and its efficiency is 96%, what must be its speed in revs/min? (8)