(Ill) In an electrostatic air cleaner (precipitator), thestrong nonuniform electric field in the central region of acylindrical capacitor (with outer and inner cylindrical radiiRa and Rb) is used to create ionized air molecules for usein charging dust and soot particles (Fig. 24-21). Understandard atmospheric conditions, if air is subjected to anelectric field magnitude that exceeds its dielectric strengthEs = 2.7 X 106N/C, air molecules will dissociate intopositively charged ions and free electrons. In a precipitator,the region within which air is ionized (the corona dischargeregion) occupies a cylindrical volume of radius R that istypically five times that of the inner cylinder. Assume aparticular precipitator is constructed with Rb = 0.10 mmand Ra = 10.0 cm. In order to create a corona dischargeregion with radius R = 5.0 Rb, what potential difference Vshould be applied between the precipitators inner and outerconducting cylinders? [Besides dissociating air, the chargedinner cylinder repels the resulting positive ions from thecorona discharge region, where they are put to use incharging dust particles, which are then collected on thenegatively charged outer cylinder.]

PH 101- Week 2 Notes 3 basic quantities to describe the motion of some system 1. Displacement- length, vector quantity (has direction/sign) a. x=x -2 1 t=t 2t 1 2. Velocity- rate at which position is changing with time; units of length/time (m/s) a. Average velocity v(overline)=x/t =(x -x )2(t1-t 2 1 b. Position-time plot (slope=average velocity) c. x=v(overline)t d. Instantaneous velocity: velocity at some instance i. Magnitude of instantaneous speed e. Suppose you want to take the instantaneous velocity at t 1 i. Slope of the tangent line at t=t 1 ii. =lim xf-x1 tft1 f -1 v=lim x -x 2 1 t2t 1 -2