12.Walang Forever.A solid infinite non-conducting cylinder has radiusR, dielectric constantK= 1, and volume charge densityρ(r) =ρ0r, whereρ0is constant and positive. What isthe electric field magnitude atr < R?31rB.ρ0R31rC.ρ0r22ε0D.ρ0r2A.ρ0R2ε03ε03ε0Solution:Use Gauss’ Law13.Flux.A circular surface of radius 2 m, with unit normalvectorˆnshown in the figure, is immersed in a uniformelectric field of magnitudeE= 4 N/C. What is the elec-tric flux on the circular surface?2/CA – 6
First Long ExamSecond Semester, AY 2014–2015Physics 7214.Spheres.Consider the spherical conductors A, B, andC that are arranged as shown. The net charges of con-ductors A and B are+5Qand-2Qrespectively. Whatis the charge of conductor C so that the outer surface ofconductor A is+4Q?Particles A, B, and C with chargesqA,qB, andqC, respectively, are arrangedas shown. For the given equipotential lines, which of the following is/areTRUEabout thecharged particles?
First Long ExamSecond Semester, AY 2014–2015Physics 7216.Russian Doll.A negatively charged conducting Russian doll consistsof spherical shaped head and base, each with radii of curvaturesRAandRBrespectively. LetVAandVBbe the electric potentials at head andbase respectively. Which of the following isTRUEabout the electricpotentials ifRA< RB?A.VA=VBB.VA< VBC.VA> VBD. Depends on the chargedistributionsSolution:Concept Only17.143Work.What is the work done by the electric field on a-4.0 Ccharge moving oppositeto the direction of a uniform electric field (3.0N/C) for a distance of0.10 m?18.GoodbyeLakas.Given the equipotential lines as shown,which of the following paths will give the least workdone by the electric field on apositivelycharged par-ticle?
First Long ExamSecond Semester, AY 2014–2015Physics 72