1 / 28

Electrostatics

Electrostatics. 10.1 Properties of Electric Charges. Static electricity – not moving Two types of charge positive (+) when electrons are lost negative (-) when electrons are gained Objects can gain charges by rubbing. 10.1 Properties of Electric Charges. Like charges repel

atalo
Download Presentation

Electrostatics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electrostatics

  2. 10.1 Properties of Electric Charges

  3. Static electricity – not moving Two types of charge positive (+) when electrons are lost negative (-) when electrons are gained Objects can gain charges by rubbing 10.1 Properties of Electric Charges

  4. Like charges repel Unlike charges attract Law of Conservation of electric charge – the net amount of electric charge produced in a process is zero 10.1 Properties of Electric Charges

  5. Robert Millikan – charge is always a multiple of a fundamental unit Quantized – occurs in discrete bundles The discrete bundle is an electron The charge on a single electron is 10.1 Properties of Electric Charges

  6. 10.2 Insulators and Conductors

  7. Conductors – outer electrons of atoms are free to move through the material Insulator – electrons tightly held, do not move 10.2 Insulators and Conductors

  8. Semiconductors – conduct electricity under some circumstances, don’t under other conditions Charges can be transferred by contact Called Charging by Conduction 10.2 Insulators and Conductors

  9. Induction – charging without contact Object is brought near a charged object Electrons move Object is grounded An electroscope measures if an object has a charge on it 10.2 Insulators and Conductors

  10. 10.3 Coulomb’s Law

  11. Electric charges apply forces to each other From experiments Force is proportional to charge Inversely proportional to square of distance 10.3 Coulomb’s Law

  12. Equation – gives magnitude of force Opposite charges – force directed toward each other Like charges – force directed away from each other Charge is measured in Coulombs 10.3 Coulomb’s Law

  13. 1 Coulomb is the amount of charge, that if placed 1 m apart would result in a force of 9x109 N Charges are quantized – that is they come in discrete values The constant k relates to the constant called the permittivity of free space 10.3 Coulomb’s Law

  14. These are forces, so be sure to use vector math, draw free body diagrams For multiple objects, require multiple free body diagram 10.3 Coulomb’s Law

  15. 10.4 The Electric Field

  16. Electrical forces act over distances Field forces, like gravity Michael Faraday electric field – extends outward from every charge and permeates all of space The field is defined by the force it applies to a test charge placed in the field 10.4 The Electric Field

  17. The Electric field would then be Or q is the test charge We can also say that Remember that E is independent of the test charge. The electric field is also a vector (free body diagrams are probably a good idea) 10.4 The Electric Field

  18. 10.5 Electric Field Lines

  19. To visualize electric fields Draw electric field lines Direction of the lines is the direction of force on a positive test charge The density of the lines indicates relative strength of the field Note: the field density increase as you get closer 10.5 Electric Field Lines

  20. For multiple charges, keep in mind • Field lines indicate the direction of the field • The actual field is tangent to the field lines • The magnitude of the field is relative to the field line density • Fields start at positive and end at negatives 10.5 Electric Field Lines Field Lines

  21. If the field is produced by two closely spaced parallel plates The field density is constant So the electric field is constant Electric Dipole – two point charges of equal magnitude but oppsite sign 10.5 Electric Field Lines

  22. 10.7 Potential Difference and Electric Potential

  23. Electricity can be viewed in terms of energy The electrostatic force is conservative because it depends on displacement Now We can calculate this value for a uniform electric field 10.7 Potential Difference and Electric Potential

  24. Positive test charge – increases when moved against the field Negative test charge – increases when moved with the field Electric Potential (Potential) – electric potential energy per unit charge 10.7 Potential Difference and Electric Potential

  25. Only difference in potential are meaningful Potential Difference (Electric Potential Difference) – is measureable Measured in volts (after Alessandro Volta) 10.7 Potential Difference and Electric Potential

  26. If we want a specific potential value at a point, we must pick a zero point. That point is usually either A. The ground B. At an infinite distance 10.7 Potential Difference and Electric Potential

  27. 10.8 Electric Potential & Potential Energy

  28. Using calculus it can be shown that the electric potential a distance r from a single point charge q is Assuming that potential is zero at infinity Like Potential Difference, this value is a scalar So 10.8 Electric Potential & Potential Energy

More Related