Electricity, magnetism and electromagnetism

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Electricity, magnetism and electromagnetism

Text of Electricity, magnetism and electromagnetism

  • 1. ELECTRICITY, MAGNETISM ANDELECTROMAGNETISM.

2. ATOMSHave neutrons, protons, and electrons. Protons are positively charged Electrons are negatively charged 3. ELECTRONS Are located on the outer edges ofatomsthey can be moved.A concentration of electrons in an atomcreates a net negative charge. If electrons are stripped away, the atombecomes positively charged. 4. THE WORLD IS FILLED WITH ELECTRICALCHARGES:++-++ ++++++--- ---- - - 5. STATIC ELECTRICITY The build up of an electric charge on thesurface of an object.The charge builds up but does not flow. Static electricity is potential energy. Itdoes not move. It is stored. 6. STATIC DISCHARGEOccurs when there is a loss of staticelectricity due to three possible things:Friction - rubbingConduction direct contactInduction through an electrical field(not direct contact) 7. ELECTRICITY THAT MOVESCurrent: The flow of electrons from oneplace to another.Measured in amperes (amps) Kinetic energy 8. HOW CAN WE CONTROL CURRENTS? With circuits. Circuit: is a path for the flow of electrons.We use wires. 9. Static electricity is stationary or collects on the surface ofan object, whereas current electricity is flowing veryrapidly through a conductor. 10. The flow of electricity in current electricity haselectrical pressure or voltage. Electriccharges flow from an area of high voltage toan area of low voltage. 11. Water pressure and voltage behave insimilar ways. 12. THERE ARE 2 TYPES OF CURRENTS: Direct Current (DC) Where electronsflow in the same direction in a wire. 13. THERE ARE 2 TYPES OF CURRENTS: Alternating Current (AC) electronsflow in different directions in a wire 14. THERE ARE 2 TYPES OF CIRCUITS: Series Circuit: the components are linedup along one path. If the circuit isbroken, all components turn off. 15. SERIES CIRCUIT 16. THERE ARE 2 TYPES OF CIRCUITS: Parallel Circuit there are severalbranching paths to the components. Ifthe circuit is broken at any one branch,only the components on that branch willturn off. 17. PARALLEL CIRCUIT 18. CONDUCTORS VS. INSULATORSConductors material through whichelectric current flows easily. Insulators materials through whichelectric current cannot move. 19. EXAMPLESConductors:MetalWaterInsulators:RubberPlasticPaper 20. WHAT IS RESISTANCE?The opposition to the flow of an electriccurrent, producing heat.The greater the resistance, the lesscurrent gets through.Good conductors have low resistance.Measured in ohms. 21. WHAT IS VOLTAGE?The measure of energy given to thecharge flowing in a circuit. The greater the voltage, the greater theforce or pressure that drives thecharge through the circuit. 22. OHMS LAWResistance = Voltage / CurrentOhms = Volts / AmpsV= IR I =V/R R=V/I 23. MAGNETISM 24. What is magnetism?Magnetism is the properties and interactions of magnetsThe earliest magnets were found naturally in the mineralmagnetite which is abundant the rock-type lodestone.These magnets were used by the ancient peoples ascompasses to guide sailing vessels. 25. Magnets produce magnetic forces and havemagnetic field lines 26. The earth is like a giant magnet!The nickel iron core of the earth gives the earth amagnetic field much like a bar magnet. 27. MAGNETS USUALLY MADE OF IRON EVERY MAGNET HAS A NORTH AND SOUTHPOLES LIKE SIMILAR CHARGES REPEL OPPOSITES ATTRACT 28. FERROMAGNETIC OBJECTS THAT CAN BE MAGNETIZED(IRON, COBALT, NICKEL) 3 TYPES OF MAGNETS LODESTONE NATURAL (PERMANENT) ARTIFICAL INDUCED ELECTROMAGNET temporary magnetsproduced by moving electric current 29. Ferromagneticmaterial such as ironattracts magneticlines of induction,whereas nonmagneticmaterial such ascopper does not. 30. Demonstration ofmagnetic lines offorce with iron filings NORTH & SOUTH POLES 31. If a single magnet isbroken into smallerand smaller pieces,baby magnets result 32. A moving charge creates a magnetic field When a charged particle is in motion a magneticforce field perpendicular to the motion is created 33. ELECTROMAGNETISM 34. ELECTROMAGNETISM A MOVING CHARGE CREATES A MAGNETICFIELD 35. RT HAND RULE Current flow direction of thumb Magnetic filed fingers 36. ELECTROMAGNET IS CREATED BY: SOLENOID: Current flowingthrough coil of wire Putting a magnet in themiddle of the coil of wireincreases the strength of theelectromagnets magneticfield 37. A coil of wire is a helix Supplied with current it is a solenoid Add an iron core simple form ofELECTROMAGNET 38. What is an electromagnet?When an electric current is passed through a coil of wirewrapped around a metal core, a very strong magneticfield is produced. This is called an electromagnet. 39. HOW ELECTRIC & MAGNETIC FIELDSINTERACTFaraday discovered that themagnetic lines of force and the wiremust have a motion relative to eachother to induce an electrical current 40. ELECTROMAGNET INDUCTION Moving a wire through a magnetic fieldwill induce a current (Faraday) Wire or field can move Moving a magnet through a coil of wirewill induce an electrical current 41. FARADAYS LAWS : OR HOW TO INCREASE THESTRENGTH OF THE INDUCED CURRENT Increase the Strength of field or size ofmagnet Increase the SPEED of motion Change the ANGLE (moreperpendicular) Increase the Number of Turns of coil 42. ELECTROMAGNET INDUCTION MOVING A BARMAGNET THROUGH ACOIL OF WIRE WILLINDUCE A CURRENTTO FLOW THROUGHTHAT WIRE 43. What are electric motors?An electric motor is a device which changes electricalenergy into mechanical energy. 44. How does an electric motor work? 45. THE PRINCIPLE OF THE ELECTRIC MOTOR 46. GENERATORS A generator is a device that uses induction toconvert mechanical energy into electrical energy. 47. TRANSFORMERSA transformer is a device used to change thevoltage in a circuit. AC currents must be used.75,000 V in thepower lines120 V in yourp = primary houses = secondary 48. Transformers areextremely usefulbecause theyefficiently changevoltage and current,while providing thesame total power. The transformer useselectromagneticinduction, similar to agenerator.