Physics 2102Exam 2CapacitorsCurrent and resistanceDC CircuitsResistors and CapacitorsCapacitors and Resistors in Series and in ParallelRC CircuitsCapacitors: Checkpoints, QuestionsProblem 25-21PowerPoint PresentationSlide 12Current and Resistance: Checkpoints, QuestionsProblem 26-56Slide 15Circuits: Checkpoints, QuestionsSlide 17Slide 18Slide 19Slide 20Magnetic Forces and TorquesCh 28: Checkpoints and QuestionsSlide 23Slide 24Physics 2102 Physics 2102 Exam 2: Review SessionExam 2: Review SessionCH 25–28CH 25–28Physics 2102Jonathan DowlingSome links on exam stress:http://appl003.lsu.edu/slas/cas.nsf/$Content/Stress+Management+Tip+1http://wso.williams.edu/orgs/peerh/stress/exams.htmlhttp://www.thecalmzone.net/Home/ExamStress.phphttp://www.staithes.demon.co.uk/exams.htmlExam 2Exam 2•(Ch 26) Capacitors: capacitance and capacitors; caps in parallel and in series, dielectrics; energy, field and potential in capacitors.•(Ch 27) Current and ResistanceCurrent and Resistance: current, current density and drift velocity; resistance and resistivity; Ohm’s law. •(Ch 28) Circuits: emf devices, loop and junction rules; resistances in series and parallel; DC single and multiloop circuits, power; RC circuits.CapacitorsCapacitorsE = /0 = q/A0E = V dq = C VC = 0A/d C = 0A/d C=0ab/(b-a)Current and resistanceCurrent and resistancei = dq/dtV = i RE = J = 0(1+(TT0))R = L/AJunction ruleDC CircuitsDC CircuitsSingle loopMultiloopV = iRP = iVLoop ruleResistors and CapacitorsResistors and Capacitors Resistors CapacitorsKey formula: V=iR Q=CVIn series: same current same charge Req=∑Rj 1/Ceq= ∑1/Cj In parallel: same voltage same voltage 1/Req= ∑1/Rj Ceq=∑CjCapacitors and ResistorsCapacitors and Resistorsin Series and in Parallelin Series and in Parallel• What’s the equivalent resistance (capacitance)?• What’s the current (charge) in each resistor (capacitor)? • What’s the potential across each resistor (capacitor)?• What’s the current (charge) delivered by the battery?RC CircuitsRC CircuitsTime constant: RC( )//0Charging: ( ) 1Discharging: ( )t RCt RCq t CE eq t q e−−= −=i(t)=dq/dtCapacitors: Checkpoints, Capacitors: Checkpoints, QuestionsQuestionsProblem 25-21When switch S is thrown to the left, the plates of capacitor 1 acquire a potential V0. Capacitors 2 and 3 are initially uncharged. The switch is now thrown to the right. What are the final charges q1, q2, and q3 on the capacitors?Current and Resistance: Checkpoints, QuestionsCurrent and Resistance: Checkpoints, QuestionsProblem 26-56A cylindrical resistor of radius 5.0mm and length 2.0 cm is made of a material that has a resistivity of 3.5x10-5 m. What are the (a) current density and (b) the potential difference when the energy dissipation rate in the resistor is 1.0W?Circuits: Checkpoints, QuestionsCircuits: Checkpoints, Questions1. HRW7 27.P.018. [406649]Figure 27-33 shows five 5.00 resistors. (Hint: For each pair of points, imagine that a battery is connected across the pair.)Fig. 27-33(a) Find the equivalent resistance between points F and H.(b) Find the equivalent resistance between points F and G.5. HRW7 27.P.046. [406629]In an RC series circuit, E = 17.0 V, R = 1.50 M, and C = 1.80 µF.(a) Calculate the time constant.(b) Find the maximum charge that will appear on the capacitor during charging.(c) How long does it take for the charge to build up to 10.0 µC?Magnetic Forces and TorquesMagnetic Forces and TorquesF q v B q E= × +r r rrBLdiFdrrr×=Brrr×=μτLvFqBmvr =Ch 28: Checkpoints and QuestionsCh 28: Checkpoints and Questions5. HRW7 28.P.024. [566302]In the figure below, a charged particle moves into a region of uniform magnetic field , goes through half a circle, and then exits that region. The particle is either a proton or an electron (you must decide which). It spends 160 ns in the region.(a) What is the magnitude of B?(b) If the particle is sent back through the magnetic field (along the same initial path) but with 3.00 times its previous kinetic energy, how much time does it spend in the field during this
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