c2 - electricity

• in a series circuit :

  • current is the same throughout
  • voltage is shared between components
  • resistance is the sum of each components resistance
• in a parallel circuit :

  • current is the sum of the current through each branch
  • voltage is the same throughout
• how does a thermistor function?

  as temperature increases, the resistance decreases
• the national grid is a network of transformers and cables distributing electricity to consumers
• transformers increase or decrease the potential difference of a current
• how does a light dependent resistor function?

  resistance decreases as light intensity increases
• what is a diodes function?

  it allows current to flow in one direction
• what is a variable resistor?

  it can change resistance
• step up transformers increase voltage, decrease current (decreases the energy lost through heating the wire.)
• the neutral wire carries electricity back to the mains
• the earth wire transfers any excess energy to the ground instead of the person
• the earth wire is yellow and green
• the neutral wire is blue
• the live wire is brown
• the live wire provides the appliance with a current
• direct current only flows in one direction
• alternating current constantly changes direction
• current is the flow of electrons
• An electrical insulator doesn’t allow electric current to pass through it
• Voltage = current x resistance
• An ammeter measures the amount of current that flows through a circuit
• A voltmeter measures voltage across components or circuits.
• What is resistance a measure of?

  how difficult it is for current to flow through a circuit
• Power = current x voltage
• Energy = power x time
• when changes of state occur, the temperature remains the same. Energy is being used to break bonds instead of increasing the temperature
• The amount of energy in an objects internal energy store is the sum of the kinetic and chemical stores of the objects particles
• Specific heat capacity is the energy required to increase the temperature of 1kg of a substance by 1 ℃
• What is specific latent heat?

  the energy required to change the state of a substance without raising its temperature
• Energy = mass x specific latent heat