Mr Palmer's AQA GCSE Physics Notes

Electricity



The National Grid












Transformers are used in the National Grid to reduce the current that travels over the power lines. The more current in the wires, the more energy is wasted as heat, and the less efficient the transmission process is. Therefore, the current needs to be as low as possible.

The electricity is transferred through the National Grid by the following method:


  1. Electricity is generated in the power station

  2. A step-up transformer is used to increase the voltage and reduce the current.

  3. The electrical energy travels down the pylons at extremely high and dangerous voltage (220,000V)

  4. A step-down transformer reduces the voltage to a safer level (220V) and increases the current so that...

  5. It can be used safely in the home





Calculating the Cost of Electricity



The teachers' kettle is turned on 50 times a day and takes two minutes to boil water. The kettle has a power rating of 1,500W. If electricity costs 7p per kWh, how much does it cost to run the kettle for a week?

Step 1: Convert W to kW



Step 2: Calculate the time used in hours














Step 3: Calculate the Energy







Step 4: Calculate the Price












 Navigation

Physics P1 Topics
  1. Heat
  2. Energy
  3. Electricity
  4. Power
  5. Electromagnetic Spectrum
  6. Nuclear Radiation
  7. Origins of the Universe


Physics P2 Topics
  1. Motion
  2. Forces
  3. Energy
  4. Static Electricity
  5. Current Electricity
  6. Mains Electricity
  7. Momentum
  8. Nuclear Physics

Other
  1. Mathematics for Physics