Electricity

• a superconductor is a material that has 0 resistivity below a certain critical temperature |
• superconductors can be used for power cables as the energy loss through heating is reduced
• superconductors can be used in magnetic fields as they would not require a constant power source
• a negative temperature coefficient means when the temperature increases, a property of a material decreases
• thermistors can be used as temperature sensors in circuits as they can trigger a certain event to happen when the temperature drops to a certain value
• an ideal ammeter has 0 resistance
• an ideal voltmeter has infinite resistance
• in a series circuit, the current is the same everywhere and the pd is shared across components
• in a parallel circuit, the current is shared between branches and the pd is the same everywhere
• kirchoffs laws

  • total current flowing into a junction = total current flowing out
  • sum of all battery voltages in a circuit = voltage of battery
• potential dividers could be created with an LDR so that a change in light intensity triggers a change in the spilt of resistance and in turn different current and pd through the other resistor
• potential dividers can be constant or variable
• emf is the work done to move 1 coulomb of charge around a circuit