PHYS 0175 1st EditionFinal Exam Study Guide Lectures: 1 - 20Lecture 1 (Jan 5)Introduction to chargeDescribe the types of possible charges. How do opposite charges interact? How do like charges interact? How can charge be created? (friction)What are the origins of electric charge?Lecture 2 (Jan 7) Differences vs conductors and insulatorsInduction vs charging by contactConductors tend to be metals, insulators nonmetals-conductorsfree flow of charge-insulatorscharges cannot move freely, cannot charge by induction-semiconductorsatom:-proton, neutron, electron-in nucleus(proton and neutron)makes up majority of weight-electron orbitalsmakes up majority of space in atom-proton and electron have equal and opposite chargesCoulomb’s lawWhat are the similarities in the equations for gravitational and electrostatic forces?Conservation of chargeWhat does quantization of charge mean?How to neutralize a chargeLecture 3 (Jan 9) These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Principle of Linear Superpositionadd x and y componentsHow to calculate r-hat-Value must always be 1 with only a direction-direction in unit vector notation or magnitude angle notationi. For a force of F21(force of 2 acting on 1) r-hat=(r1-r2)/r where r is the distance between the two charges, r1 and r2 are distances from the origin(can use vector coordinates i,j,k hatsTorque problems-consider forces at pivot point-clockwise or counterclockwise-rxF-torque on Electric diple is a force produced externally! Torque!=0, but Fnet=0Electric Field produced by dipole vs electric field(and force) acting on a dipoleWhat is necessary to create an electric field? What must be present to detect and electric field?-assume test charge is negligibleLecture 4 (Jan 12) F=qERegion around point charge=spherical symmetryWhat types of charges point inward? What types point outward?-Electric field lines are not physically real!If single point charge-straight electric field lines b/c not affectedif dipole(2 equal and opposite charges near on another)-will curve because their forces act on each other = & opp-lines never crosswhat happens to the field lines of two line charges? To unlike charges?Lecture 5 (Jan 14) Dipole moment p=qdPoints from – to +Torque on dipole and dipole U(potential energy)When is it in stable equilibrium(U=0)? Unstable(U=max)? U=-pEcos(theta)Electric dipole at a distance?Continuous charge distributions(requires integration)-rod-disk-layers-R infinity infinite sheet-ring-ring at a distancewill only need to integrate if these are not standard shapes(ie half a ring, disk etc)units for E?When to use areal charge density vs surface charge densityLecture 6 (Jan 16) Electron oscillating about ringIf the ring is positively charged, will the electron stay at the center?Between two parallel charged platesWhere do the electric fields not cancel?(middle)Does it matter where in the middle?(hint uniform electric field)Acceleration of proton/electron(one plate on top, one on bottom)Analogous to a parabola(except can move up or downwards)x-component of velocity constant, y-cmponent has accelerationuse kinematics equationsLecture 7 (Jan 21) Flux-volume flow rate of chargeCalculating flux itself is not as useful as calculating electric field!Electric field must penetrate surface, if simply glides, then that side has no fluxSI units?Dot productloses directionWhat type of surface makes a guassian(imaginary) surface ideal?Does size or shape matter?Does external charge/flux ever contribute?Surface must be enclosed!Lecture 8 (Jan 23) Goal of guass’ lawto find a surface where E is constant and independent of radius/distance to object of charge, so that we can take it out of the surface integralMay have linear superpositionTake two ie spheres, treated separately-but both must include point P(observer)Find flux of one then add to other with use of the different Gaussian surfacesShell theoremsLecture 10 (Feb 28)Work and potential energyOvercome repulsionWhat is the point of 0 U?How does potential energy change with respect to direction of electric field?Positive charge:Going with the Electric fieldpositive WdeltaU decreases(negative)W=-deltaUGoing vs Elect. Field- W negativeDelta U positive(increases)Since Elect. Field points toward negative qMoving away/against- toward same charge + unfavorableNegative charge:Going with Elect Field -W, +deltaU(U increases)Going vs negative charge(same repel)Lecture 11What is the algorithm for total electric potential energy?Ie Making up for “double counting”Can also take ½Assemble chargesHow much U is there in a single charge?U is mutual interactionAlone=0Application of conservation of energyFinding speedElectric force conservativePotential-Independent of test qPotential increases against the fieldLecture 12Potential on line of chargeCoordinate systemIntegrateLinear charge density lambdaEquipotential surfacesElectric field is the –1*potential gradientPartial derivativesLecture 13Relation between charge density and radiusBetween equipotential surfacesLecture 14What is capacitance?Only depends on geometry-not on chargeThe greater the capacitance, the lower the potential, the less work neededEnergy densityPositive charges flow from higher to lower VTechnically e- movingPlate is initially neutralInduced by battery(emf) that causes potential differenceLecture 15What is special about plates in ||?Par-V equipotentialCharges passing through vary depending on CCeq=C1+C2…Can find charge ratio(if two parallel in series to another capacitor plate with known charge or capacitance and voltage)In series?Same charge passing throughPotential depends on capacitanceCeq=reciprocal of sum of reciprocalsCylindrical and spherical capacitorsIntegrating potential with dot product(E*d)dl=-drbecause integrating from outside in, while electric field is pointing outDielectric materialsEffect on Elec. FieldDecreases due to induced dipoleIntegrate with gauss’ law for dielectricUse fluxLecture 16Two dielectrics if equal areasMean of dielectric constantElectric Current-scalarAlso higher to lower V(Scalar)Drift speed caused by presence of an electric fieldcurrent densityflux integral for current densityResistance and resistivityRelation with area, lengthLecture 17Current densityDirection depends on sign of chargeIf +same dir as drift velocityCan only take current density out of