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# Energy & Electricity

## on Oct 26, 2008

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This is a powerpoint on energy and electricity its really usefull

This is a powerpoint on energy and electricity its really usefull

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## Energy & ElectricityPresentation Transcript

• Energy & Electricity Year 9 module on Electricity as a convenient form of energy © N.R.Wheeler, 2004
• Energy Resources © N.R.Wheeler, 2004 Wind Fossil Fuels Solar Nuclear Hydroelectric Geothermal
• Energy Types © N.R.Wheeler, 2004 Gravitational Potential : due to height Chemical Potential : found in food and fuels Sound : produced by the voice Thermal : hot objects Light : bright objects Magnetic Electric
• Energy © N.R.Wheeler, 2004 Resources Types Note : Coal, Oil and Gas = Fossil fuels Magnetic Electrostatic Chemical Elastic (spring) Kinetic (movement) Gravitational Potential Nuclear Electrical Sound Light Thermal (heat) Geothermal Solar Biomass Hydroelectric Wave Wind Nuclear Gas Oil Coal
• Measuring Current © N.R.Wheeler, 2004 Current is measured in units called ‘amperes’ or ‘amps’. Current is measured using an ‘Ammeter’. Ammeters are always connected in SERIES with all the other components in a circuit.
• CURRENT FLOW © N.R.Wheeler, 2004 Current measurements Ammeter 1 = 3.0 amps Ammeter 2 = 1.5 amps What are the readings on the other ammeters? Hint : the length of the wires makes no difference and you cannot lose current in a circuit ! NOTE : the series connection of each ammeter.
• Measuring Voltage © N.R.Wheeler, 2004 Voltage is measured using a ‘voltmeter’. Voltage is measured in units called ‘Volts’. Voltmeters are always connected in PARALLEL to the component being measured in a circuit. NOTE : the main circuit has components in series.
• VOLTAGE SUM © N.R.Wheeler, 2004 Voltage measurements Voltmeter 1 = 1.5 volts Voltmeter 2 = 0.9 volts What is the voltage across the resistor, voltmeter 3 ? Hint : The total must be the same as the supply voltage. NOTE : the main circuit has components in series.
• Series and Parallel © N.R.Wheeler, 2004
• SERIES CIRCUITS
• Components one after the other
• Same current through all components
• Different voltages across each component
• Energy of supply shared
• PARALLEL CIRCUITS
• Components side by side
• Different current through each components
• Same voltages across each component
• Energy of supply identical
• WATER CIRCUIT MODEL © N.R.Wheeler, 2004
• Which part represents :-
• a) battery
• b) wires
• resistance
• switch
What is wrong with the model ?
• SKI LIFT MODEL © N.R.Wheeler, 2004
• Which part represents :-
• wires
• resistance
• current
• voltage
What is wrong with the model ?
• Voltaic Pile (battery) © N.R.Wheeler, 2004 A battery is a collection of cells that converts chemical to electrical energy.
• Power Station © N.R.Wheeler, 2004 Overall chemical energy is converted into electrical energy, which is a convenient form for a consumer.
• Sankey Diagram © N.R.Wheeler, 2004 The width of the arrow represents to proportion of energy that is supplied (100%), used or wasted.
• Wasted Energy © N.R.Wheeler, 2004 Very little of the supplied energy is useful in a light bulb.
• Sound Electricity © N.R.Wheeler, 2004 Can you construct the two Sankey diagrams for the energy transfers involving a loudspeaker and a microphone. 30% Efficiency 10% Efficiency
• Warming Energy © N.R.Wheeler, 2004 Can you draw the Sankey diagram for this room heater?
• EFFICIENCY Fill in the unknown values. ? 72000 96000 Lift 120 ? 600 Food Mixer 10 10 ? Radio ? 1960 2000 Kettle 21 2 ? Fluorescent Bulb 98 2 100 Filament bulb Wasted Energy (J) Useful Energy (J) Energy Supplied (J) Appliance