1 / 28

PSC 4011

PSC 4011. Electricity: What’s the connection?. PSC 4011: Static Electricity & Magnetism. Electricity describes all of the phenomena caused by positive charges ( protons ) and negative charges ( electrons )

harrison-santiago
Download Presentation

PSC 4011

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. PSC 4011 Electricity: What’s the connection?

  2. PSC 4011: Static Electricity & Magnetism • Electricity describes all of the phenomena caused by positive charges (protons) and negative charges (electrons) • If a body (atom/molecule or object) has MORE PROTONS than electrons, it will be positively charged. • If a body has MORE ELECTRONS than protons, it will be negatively charged.

  3. PSC 4011: Static Electricity & Magnetism • Electrically charged objects, which have gained or lost ELECTRONS, tend to exert a force on other objects nearby. • Like charges (+ + or - - ) will tend to REPEL each other. • Opposite charges (+ - ) will tend to ATTRACTeach other. • Charges, are conserved.

  4. PSC 4011: Static Electricity & Magnetism • When an object has the exact same number of protons and electrons it is called NEUTRAL. • Charging an object consists in creating an imbalance in the electrical charge of that object. • Materials can be divided in three groups, according to their reaction to the process of “charging”: • Conductors • Semiconductors • Insulators

  5. PSC 4011: Static Electricity & Magnetism • Every object fits somewhere along this conducting continuum • Where do you think the human body would fit in the above diagram?

  6. PSC 4011: Static Electricity & Magnetism Conductors : permit the free flow of electrical charges. • When charged, its electrons move in one general direction, pushing one another and making the charge move along the circuit. • Metals and electrolytic solutions are conductors (ions).

  7. PSC 4011: Static Electricity & Magnetism Insulators: impede the free flow of electrical charges. • When charged, its electrons are strongly held by the atomic nuclei, so charges do not move. • Wood, glass, plastic, ceramics, paper, rubber, silk and air are also insulators.

  8. PSC 4011: Static Electricity & Magnetism Static electricity (electrostatics) describes all the phenomena related to electrical charges at rest. • Charges are at rest when they are INSULATED. • Static charge is often detected by a device known as an electroscope. • There are three methods for charging objects.

  9. PSC 4011: Static Electricity & Magnetism

  10. PSC 4011: Static Electricity & Magnetism Charging by friction: • Two neutral bodies rubbed against each other. • Some electrons are pulled from one of them. • Resulting: two opposite charged bodies (attraction!)

  11. PSC 4011: Static Electricity & Magnetism Charging by friction:

  12. PSC 4011: Static Electricity & Magnetism Charging by conduction: • Two solid bodies in contact with each other. • The charge is transferred from the charged object to the second object. • Resulting: two equally charged bodies, each with less charge than initially

  13. PSC 4011: Static Electricity & Magnetism

  14. PSC 4011: Static Electricity & Magnetism Charging by induction:

  15. PSC 4011: Static Electricity & Magnetism Charging by induction:

  16. PSC 4011: Static Electricity & Magnetism Charging by induction:

  17. PSC 4011: Static Electricity & Magnetism Precautions (Static Electricity): Objects must be grounded in order to eliminate static charge built on them

  18. PSC 4011: Static Electricity & Magnetism Applications (Static Electricity): Objects are previously electrified, so their charge is kept, and attraction is guaranteed when in use

  19. PSC 4011: Static Electricity & Magnetism • Coulomb’s law states that the magnitude of the force between two immobile and electrically charged particles is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. • Fe: electrical force (in N) • k: Coulomb’s constatnt (9 x 109 Nm2/C2) • q1: charge of particle 1 (in C) • q2: charge of particle 2 (in C) • r: distance between the two particles • Only valid for charges at rest.

  20. PSC 4011: Static Electricity & Magnetism Example 1: For two positively charged particles, each with a charge of 5x10-8C and placed 1cm apart. Calculate the electrical force between the two particles:

  21. PSC 4011: Static Electricity & Magnetism Fe = k(q1)(q2)/r2 Fe = (9 x 109Nm2/C2)(5 x 10-8C)(5 x 10-8C)/(0.01m)2 Fe = (9 x 5 x 5) x 10 [9+(-8)+(-8)] / (0.0001) (Nm2/C2)(C)(C) / (m2) Fe = (225) x 10-7/ 1 x 10-4N Fe = [(225)/1] x 10[(-7)-(-4)] N Fe = 225x 10-3N Fe= 0.225 N

  22. PSC 4011: Static Electricity & Magnetism Magnetism: Physical phenomenon produced by the motion of charge, resulting in attractive and repulsive forces between objects

  23. PSC 4011: Static Electricity & Magnetism

  24. PSC 4011: Static Electricity & Magnetism Magnets: Objects upon which magnetism is observed. Magnets ALWAYS have two poles: North and South (if you break a magnet, you create two smaller magnets, each with its north and south poles)

  25. PSC 4011: Static Electricity & Magnetism Magnetic field: Magnetic influence of a magnet on its surroundings. Magnetic field lines: Representation of the magnetic field of a magnet. Lines exit North pole Lines enter South pole

  26. PSC 4011: Static Electricity & Magnetism Attraction Repulsion

  27. PSC 4011: Static Electricity & Magnetism Earth is a gigantic magnet

  28. PSC 4011: Static Electricity & Magnetism

More Related