glossary terms

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glossary terms
2012-10-30 20:31:20
science chapter 11

science chapter 11 glossary terms
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  1. Electric circuit
    • A closed path along which electrons that are powered by an energy source can flow.
    • eg. battery, generator, motor
  2. Voltaic cell
    Asource of energy that generates an electric current by chemical reactions involving two different metals or metal compounds separated by a solution that is a conductor.
  3. Battery
    • A connection of 2 or more cells
    • 1 cell = 1.5 V
  4. Electrode
    • One of two metal terminals in a cell or battery
    • the breakdown of an electrode is one factor that can limit the life of a cell
  5. Electrolyte
    An electrolyte is a solution or paste that conducts charge
  6. Dry cell
    A dry cell is a cell that contains an electrolyte that is a paste
  7. Wet cell
    A wet cell is a cell that contains a liquid electrolyte
  8. Primary cell
    A cell that can be used only once
  9. Secondary cell
    A cell that can be recharged
  10. Fuel cell
    • A cell that generates electricity through the chemical reactions of fuel that is stored outside the cell
    • - hydrogen fuel cell combines with hydrogen that is stored in a tank or cartrige with oxygen from the air
    • - by-products are heat and water
  11. Solar cell
    • A solar cell is a cell that converts sunlight into electrical energy.
    • eg. solar panel
  12. Terminal
    the positive and negative terminals of a cell must be connected to other components in the circuit, in order for electrons to flow from, and return to, the cell/battery/energy source.
  13. Switch
    A switch is a control device. It is a conductor that can complete or break the circuit it is connected to.
  14. Open circuit
    • An open circuit is a circuit that contains a gap or breaks.
    • eg. opening a switch in a circuit
  15. Electric current
    • Electric current is the flow of electrons through a closed path.
    • Current is measured in ampere's (A).
  16. Coulomb (C)
    A coulomb is a unit of measurement. One coulomb is is the quantity of charge that is equal to the charge of 6.25 x 1018  electrons
  17. Ampere (A)
    • An ampere is the unit of electric current (A).
    • Electric current is measured using an ammeter.
    • eg. a current of 1.0A in a circuit means that 1.0 C of charge passes a given point in a circuit every second.
  18. Electrical resistance
    • Electrical resistance is a property of a substance that hinders electric current and converts electrical energy into other forms of energy
    • A resistor is a device used in an electric circuit to decrease the current through a component by a specific amount.
    • eg. metals have lower resistance than non-metals
  19. Resistor
    A resistor is a device used in an electric circuit to decrease the current through a component by a specific amount.
  20. Load
    A load is a resistor or any other device that transferres electrical energy into heat, motion, sound, or light.
  21. Potential difference (V)
    • Unit of measurement  = volts.
    • the voltage of a cell is related to the amount of work that is done on each coulomb of charge that moves between the terminals of the cell
  22. Volt
    Unit used to measure potential difference
  23. Circuit diagram
    A diagram that uses standard symbols to represent the components in an electric circuit and their connections.
  24. Series circuit
    A circuit in which there is only one path along which electrons can flow
  25. Parallel circuit
    A circuit in which there is more than one path along which electrons can flow.
  26. Ohm's law
    • Ohm's law is; the ratio of potential difference to current is a constant called resistance
    • ohms law is often written as
    • One concequence is that the larger the resistance,  the smaller the current.
  27. Ohm
    An ohm is the unit of resistance, equivilent to one volt per Ampere. (V/A)
  28. Superconductor
    A superconductor is a material through which electric charge can flow with no resistance.
  29. Non- ohmic
    If a load does not have constant resistance, it does not follow ohm's law; therefor it is considered non-ohmic.
  30. Loads in a series
    • Loads, such as bulbs, transform electrical energy into other forms of energy. the total energy that is transformed by the current through the entire circuit must equal the work that is done by the cell.
    • IT = I1=I2=I3               VT= V1 + V2 + V       RT= R1+ R2 + R3
  31. Loads in parallel
    • At a parallel connection, there is more than one path along which electrons can flow.
    • The sum of the currents through each path of a parallel connection equals the current entering the connection.