Topic 2 (electricity)

• How to investigate a filament lamp, diode, and resistor?

  1. Set up the circuit shown
  2. turn power supply to 2v
  3. take readings of voltage and current on voltmeter and ampmeter
  4. calculate resistance
  5. change power supply to 4,6,8, and 10v and repeat steps 2-4
  6. reverse positive and negative wires and repeat steps 2-5
  7. replace lamp with different component and repeat steps 2-7

  
• What is charge?


  The flow of electrons in a circuit
• What does the triangle for specific latent heat look like?

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• How to find the density of an irregular object?

  Measure the mass using scales

  place a eureka can on a brick. Put a beaker under the spout and fill the can with water

  Place a measuring cylider under the spout when it has finished dripping

  tie the object to string and lower it into the can

  measure the volume of spilt water and calculate density
• what is amps?


  The current numbr of electrons flowing through a circuit
• in a series circuit what are the rules for current and potential difference?

  the same current passes through each component. the potential difference is shared by each component
• What is power?

  the amount of energy something uses per second
• What is the triangle for resistance?


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• How to calulate power?

  Energy transferred to the appliance / time taken to do so
• What is potential difference?

  the energy carried in the circuit. it is the same as volts
• How to find the total resistance in a series circuit?

  Two or more components is equal to the sum of resistance in each component
• How to find the density of a regular object?

  measure the length, width and height.

  record results

  measure the mass using a digital balance and record

  calculate volume

  calculate density
• How to calculate volume?

  width x height x length
• Wha does the graph look like for a thermistor?

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• What is specific latent heat?

  The amount of energy needed to convert 1kg of a substance from one state to another without changing the temperature
• What 2 things does increasing the energy of something do?

  changes the state

  raises temperature
• What is the triangle for density?


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• Fill in a table for the colour and purpose of the live, earth and neutral wire

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• How to calculate current?

  Current = charge/time
• What is the triangle for specific heat capacity?


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• How to find the density of a liquid?

  place measuring cylinder on balance and record mass

  pour 50cm3 of liquid into the cylinder and record new mass

  subtract the first mass from the second.

  use this to calculate density
• How to calculate efficiency?

  (Output power / input power) x100
• What is charge carried by?

  protons and electrons
• What does the graph for a filament lamp look like?

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• What does the graph look like for a light dependant resistor?


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• What does the graph look like for a diode?


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• What is the rule for potential difference in a parralel circuit?

  The potential difference is the same across all components in a parallel circuit.
• In a direct current the electrons travel out of

  the negative and into the positive end of the cell
• In alternating current the voltage changes from 325V to -325V at a rate of 50Hz
• How to calculate frequency?

  1/ time for one wave to pass
• What will happen if the live wire is touching the casing of the plug?

  The casing becomes live
• Why is the outer insulation of a plug plastic?

  Plastic can’t conduct electricity
• How to calculate volts?

  Current x resistance