Physics 212: Exam 1 Study Guide
Physics 212: Exam 1 Study Guide PHYS 212
Popular in Electromagnetism
Popular in Physics
This 6 page Study Guide was uploaded by Alyssa Grube on Sunday September 18, 2016. The Study Guide belongs to PHYS 212 at University of Pennsylvania taught by Dr. Van Hook in Fall 2016. Since its upload, it has received 9 views. For similar materials see Electromagnetism in Physics at University of Pennsylvania.
Reviews for Physics 212: Exam 1 Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/18/16
Physics 212: Electromagnetism Chapters 2527 in Physics for Scientists and Engineers by Randall Knight Topics by Chapter: Chapter Section Topic 25 1 Developing a Charge Model 2 Charge 3 Insulators and Conductors 4 Coulomb’s Law 5 The Field Model 26 1 Electric Field Models 2 Electric Field of Multiple Point Charges 3 Electric Field of a Continuous Charge Distribution 4 Electric Fields of Rings, Planes, and Spheres 5 ParallelPlate Capacitor 6 Motion of a Charged Particle in an Electric Field 7 Motion of a Dipole in an Electric Field 27 1 Symmetry 2 The Concept of Flux 3 Calculating Electric Flux 4 Gauss’s Law 5 Using Gauss’s Law 6 Conductors in Electrostatic Equilibriumd Chapter 25 1. Frictional forces create charge in an objectthe process is called charging. 2. Like charges repulse each other, opposite charges attract. 3. Charge can be transferred between objects when they touch, called discharging. 4. Conductors are objects through or along which charge traveled. 5. Insulators are materials on or in which charge remains immobile. 6. Charge is a property of protons or electrons, the basic charge of all matter. 7. Law of Conservation of Charge: Charge is neither created nor destroyed. 8. The electrons in an insulator are bound to the positive nuclei. Charging an insulator by friction leaves patches of immobile molecular ions on the surface. 9. The motion of charges through a material is called a current, and the charges that move are called charge carriers. 10. Charge is free to move through metals because there is a sea of electrons that are free to move. 11. Electrons in a conductor are free to move. 12. Electrostatic equilibrium occurs when there is no net force on any charge. If there were a force, it would move back to a zero point. 13. Excess charge is located on the surface of an isolated conductor. 14. Any object that is connected to the Earth through a conductor is grounded. 15. Charge polarization is the slight separation of the positive and negative charges in a neutral object. 16. The polarization force causes the charge separation to occur. 17. If something is polarized the net charge is still zero, charging gives a net charge that is not zero. 18. Two opposite charges with a slight separation is called a dipole, of which there are induced and permanent forms. 19. Coulomb’s Law only applies to point charges. 20. Electric forces can be superimposed. 21. Source charges alter the space around them by creating an electric field. 22. The electric field created by the source charge exerts a force on a second charge. 23. The magnitude of the electric field is called the electric field strength. 24. The field is the agent that exerts an electric force on a charged particle. 25. The electric field is a vector field. 26. If q (the charge) is positive then the electric field vector points in the same direction as the force on the charge. 27. The electric field does not depend on the size of the charge used to probe the field because the force is proportional to q, so the electric field is independent of the charge that probes the field. The field is dependent only on the source charges. 28. A field diagram can be constructed if a sufficient number of points in space. 29. A field diagram points away from positive charges and towards negative charges. Important Notes: Coulomb’s Law and Units of Charge pgs. 732733; example problems pgs. 734735; Equation 25.5 and 25.6 pg. 738; Example problem pg. 738739; Equation 25.7, 25.8 and 25.9 pgs. 739740; Example problems pgs. 740742. Chapter 26 1. The net electric field is its vector sum due to each point charge. 2. An electric dipole is two equal but opposite charges separated by a small distance. 3. Oppositely charged particles that maintain a permanent separation are a permanent dipole. 4. An induced electric dipole can be created by polarizing a neutral atom with an external electric field. 5. The dipole moment points from the negative to the positive charge, and identifies the orientation of the dipole. 6. The electric field points in the opposite direction from the dipole. 7. Electric field lines are a way to visualize the electric field. 8. Electric fields point from the positive charge and towards the negative charge. 9. Linear charge density is the amount of charge per meter of length. 10. Surface charge density is the amount of charge per square meter. 11. Uniformly charged objects have charges that are evenly spread through that object. 12. Electrodes are charged flat surfaces used to steer electrons on the proper paths. 13. Electrodes can be modeled as an infinite plane of charge as long as the distance to the electrode is much smaller in comparison than the distance to the edges. 14. A sphere of charge has an external electric field equal to a point charge at its center. 15. A parallelplate capacitor is two electrodes charged equally but oppositely. 16. All charge of a parallelplate capacitor is on the inner surfaces of the two plates, so they can be modeled as two planes of charge with equal and opposite surface charge densities. 17. The electric field of the plates points towards the negatively charged plate. 18. The fringe field is the weak field outside of the parallel plate capacitor. 19. The shape of the electrodes is unimportant if they are close enough together. 20. If the electric field has the same strength and direction at every point in a region of space it is called a uniform electric field. 21. The easiest way to produce a uniform electric field is with a parallelplate capacitor. 22. Electric field problems with uniform electric fields carry the assumption that such problems occur inside a parallelplate capacitor. 23. The electric field created by the source charges exerts a force on the charge, causing the charged particle to accelerate in response to this force. 24. The charge to mass ratio determines a particles acceleration. Charges with different charges and masses but the same charge to mass ratio will undergo the same acceleration and trajectory. 25. A charged particle will move in an electric field with constant acceleration because a uniform electric field is constant everywhere. 26. Kinematics can be used to determine the motions of a charged particle in a uniform electric field. 27. There is no net force on a dipole in a uniform electric field. 28. The net force on a dipole in a nonuniform electric field is towards the direction of the strongest field. 29. Any charged object will cause the dipole to experience a net force towards itself. Important Notes: Strategy/Tactics pgs. 752, 755, 758; Example Problems pgs. 752753, 755, 758759, 760761, 763, 765766, 766, 768, 769, 771, 772; Equations pgs. 753755, 757, 760767, 770 Chapter 27 1. A charge distribution is symmetric if geometric transformations do not cause any physical change (translations, rotations, reflections). 2. The electric field symmetry must match the symmetry of the charge distribution. If this were untrue, then the electric field could be used to test if the charge distribution had undergone a transformation. 3. A cylindrically symmetric charge distribution with an electric field cannot have a component parallel to the cylinder axis. 4. A cylindrically symmetric charge distribution with an electric field cannot have a component tangent to the cylindrical cross section. 5. Symmetry arguments allow many field shapes to be disproven. The process of elimination can lead to the actual shape of the field. 6. The three fundamental symmetries are planar, cylindrical, and spherical symmetries. 7. A Gaussian surface is a closed surface through which an electric field passes. 8. A spherical Gaussian surface has a field that is everywhere perpendicular to the surface. 9. A cylindrical Gaussian surface has a field that is perpendicular to the curved wall and no field passes through the flat top and bottom. 10. The electric field flows out of a closed surface with a positive charge and into a closed surface with a negative charge. 11. The electric field pattern is simple if the closed surfaces matches the symmetry of the charge distribution inside of it. 12. The electric flux is the amount of electric field passing through a surface. An outward flux for a positive charge, and inward flux for a negative charge, and no flux for a neutral charge. 13. Calculating flux pgs. 785790 14. Gauss’s Law can be used to find the electric fields of some continuous distributions of charge more easily than Coulomb’s Law. 15. Gauss’s Law is true for moving charges where Coulomb’s Law is not. 16. The Guassian surface has the same symmetry as the electric field. 17. Electric flux is independent of the surface shape and radius because the Gaussian surface can be cut up into small pieces and added together, much like an integral. 18. The net electric flux through a closed surface containing no net charge is zero because the electric field flows into and then out of the surface and thus the summation cancels itself out. 19. Gauss’s Law applies only to closed surfaces, is not a physical surface but imaginary, and cannot be used alone to find the electric field. It needs to be applied in cases where the shape of the electric field can be deduced. 20. The electric field at all points of a conductor in electrostatic equilibrium is zero. 21. All the excess charge of a conductor rests on the exterior surface. 22. The electric field on the surface of a conductor must be perpendicular to its surface. 23. The surface charge density is not constant on the surface of the conductor and instead depends on the surface of that conductor. 24. Screening is the use of a conducting box to exclude electric field from a region of space. 25. A Faraday cage (wire mesh or screen) can be used to screen sufficiently, but solid metal walls are ideal. Important Notes: Strategy/Tactics pgs. 789, 791, 795; Example Problems pgs. 787, 790, 795796, 796798, 801802; Equations pgs. 786794, 799
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'