Problem (4) An ESP is treating the flue gas from a coal combustion unit and achieving a 97\% PM removal efficiency. Suddenly the efficiency drops to 92%, but the gas flow rate has remained exactly the same. a. Estimate the ratio of the new effective drift velocity (wc) to the old we. b. Under the old conditions (while achieving 97% efficiency), the fly-ash resistivity was measured at 3.161010ohmcm. Estimate the value of the new drift velocity, m/min. c. Discus how we can resolve this decline in efficiency