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Chapter 6 – Electricity. 6.1 Electric Charge Positive and Negative Charges Matter is composed of _______ Atoms are composed of protons, neutrons and electrons.

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Presentation on theme: "Chapter 6 – Electricity. 6.1 Electric Charge Positive and Negative Charges Matter is composed of _______ Atoms are composed of protons, neutrons and electrons."— Presentation transcript:

1 Chapter 6 – Electricity

2 6.1 Electric Charge Positive and Negative Charges Matter is composed of _______ Atoms are composed of protons, neutrons and electrons The amount of positive charge on a proton is _____ to the amount of negative charge on an electron Atoms have _______________ (electrically neutral) Amount of electric charge is measured in ________ (C)  6,250 million billion protons in 1 C of electric charge  6,250 million billion electrons in -1 C of electric charge Coulomb's Law: Like charges _____ and opposite charges _______. Atoms equal no electric charge coulombs repel attract

3 The difference between the # of protons and the # of electrons determines an object’s ___________; therefore  (-) charged obj. have ______ electrons.  (+) charged obj. have ______electrons.  Obj. are charged by the _______of electrons. electric charge more fewer transfer

4 Transferring Charge Electrons are _______________ to some atoms and molecules than others Some atoms can _______electrons more easily than others Leads to an buildup of electrons on other substances (excess negative charge)  _____________ bound more tightly transfer Static electricity


6 Law of Conservation of Charge  Charge can be _________ from object to object, but it _______ be _______or _________ Law of Conservation of Charge  Charge can be _________ from object to object, but it _______ be _______or _________ transferred cannot created destroyed

7 Charges Exert Force The force between electric charges depends on ________between charges ________of charge _____ Distance Amount Mass

8 _______________ have similar properties. On this scale gravity dominates! Gravitational Forces

9 Comparing Electric Forces and Gravitational Forces Force of gravity is much ______ than electric force – Electric force between a proton and an electron in a hydrogen atom is about a thousand trillion trillion trillion times larger (10 39 X) than the gravitational force between the same particles. Chemical bonds in molecules are due to _______ forces between atoms – Much larger than the ___________ forces between the atoms weaker electrical gravitational

10 On this scale ___________ dominates! electrical force

11 Electric Fields Surround every electric charge and exerts the force that causes other electric charges to be _________ or ________. Do not need to be ________ to exert force on each other Any charge that is placed in an electric field will be ______ or _______ by the field Electric Field Near Negative Charge attracted repelled touching pushedpulled

12 Conductors and Insulators Conductor Material through which ____________________ Best electrical conductors are ________ Conductors have _____ resistance? Insulator Material in which electrons are ____________________ Electrons are held ______________ that make up insulators Best insulators are _____, ______, ______ and ________. Insulators have a _____ resistance electrons move easily metals low not able to move easily tightly to atoms glass plasticrubber ceramic high

13 Conductors and Insulators

14 Types of Charging Charging by Contact The process of transferring charge by _________ or ________. Also called charging by ___________ Charging by Induction The _______________ of electrons on a _________ object caused by a _______ object touching rubbing conduction rearrangement neutral nearby

15 Lightning

16 6.1 Summary 2 types of electric charges are (+) & (-). Like charges repel, unlike charges attract. On molecular level, electric force is stronger than gravitational force Electric force acts through electric fields. Electric fields surround charged objects. Any charged object that enters a region with an electric field experiences an electric force. Electrons move easily through conductors Electrons do not move easily through insulators

17 6.2 Electric Current Current and Voltage Difference ________________: the net movement of electric charges in a single direction Measured in _________ (A) 1 ampere = __________________________ A voltage causes charges to move, which in turn produces a _______. A circuit must be ______ for a current to be produced. Electric current amperes 1 Coulomb of electric charge current closed

18 position A charged object has electric PE due to its position in an electric field. Potential difference or ________ is the difference in electrical PE per unit charge. – SI unit for pot. diff. (V) = volts = 1Joule/coulomb – Ex. 12V vs. 9V voltage

19 Electric current is from _____ voltage to _____voltage Voltage difference is related to the _____________________________ Voltage difference is measured in _____ (V) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Charge Flow Current Low VoltageHigh Voltage higher lower force that causes electric charges to flow volts

20 ___________: a closed path that electric current follows Electric circuit

21 Current and Flow Direction The _______ of the electric current is always from a _____ voltage to a _____ voltage, but … The _______ in a _____actually flow from a _____ voltage to a _____ voltage direction higher lower electrons circuit lower higher

22 Batteries Dry – Cell Batteries Consist of ___________ surrounded by a material called an ___________ Electrolyte enables ________ to move from one electrode to another _________________ occurs when the 2 terminals are connected in a ________. ________ difference between these 2 terminals causes a current through a ____________. Example: _______________ Wet – Cell Batteries Contains _________________ made of different _______ or _________ compounds in an ___________ The electrolyte is a ____________________ Example: __________ 2 electrodes electrolyte charges Chemical reaction circuit Voltage Closed ciruit Flashlight battery 2 Connected plates metals metallic electrolyte conducting liquid solution Car battery

23 Dry - CellWet - Cell Anode (negative) Cathode (positive )

24 Resistance ___________: the tendency for a material to resist the flow of electrons and to convert electrical energy into other forms of energy ohms – Measured in ohms ( ) Caused by _____________ which slows the movement of ____________________________ Resistor: ______________ _______________________ ______________________ Resistance internal friction charges through conducting material A special type of conductor used to control current.

25 Superconductor Certain metals and compounds that have _____ resistance when their temp. falls below a certain temp called ______ __________. zero critical temperature

26 Semiconductor Semiconductors in _________ are ________. However, as atoms/impurities are added, or become compounds, these materials begin to be able to ___________________. pure state insulators conduct electric charge

27 Schematic Diagram or drawing used to build a _______. There are two types of circuits. – ________: one path for electrons, if one bulb goes out they all do – _________: more than one path for electrons, if one bulb goes out the rest can still shine circuit Series Parallel

28 Series and Parallel Schematics

29 Schematic Symbols- Draw symbols on the right side margin of notes

30 2 Schematic Symbols Ammeter read currents in amps Voltmeter reads potential difference in volts

31 Series Circuit

32 Parallel Circuit

33 Open vs Closed Circuit ______circuit allows electron to flow, lights on ______ circuit does not, lights off Closed Open

34 Circuit Breakers and Fuses Too many appliances on at the same time in a home cause the overall resistance of the circuit to be lowered. – Result is a circuit carrying more electrical current than is safe it is ___________. Fires can result when this happens. – _______________ act as a switch and open the circuit. overloaded Circuit breakers

35 Formulas SI unit for electric charge – _________ is the quantity of the electricity transported in one second by the current of one ampere. Symbol: Potential difference, voltage (V) – 1Joule/coulomb (1J/C) Unit for Current (I) = Ampere (amp-A) Unit for Resistance (R) = Ohm Ω – Formula : Resistance = Volts/Current – Formula with symbols: Ω = V / I Unit for Electric Power (P) = Watts (Watts) --- Formula: Power = Volts x Current --- Formula with symbols: P= V x I Amps vs volts: (C)


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