GCSE PHYSICS: Energy

GCSE PHYSICS: Energy

1. The law of conservation of energy is a law of science that states that energy cannot be created or destroyed, but only changed from one form into another or transferred from one object to another.

2. Types of Energy

   • Electrical
   • Gravitational Potential = stored energy in raised objects
   • Kinetic = The energy in moving objects
   • Magnetic = Energy in magnets and Electromagnets
   • Thermal Energy
   • Chemical = stored energy in fuel, foods and batteries
   • Light/Radiant Energy
   • Sound
   • Elastic Potential

3. Energy Processes

   • This diagram shows the energy transfer diagram for the useful energy transfer in an electric lamp. You can see that the electric lamp transfers or converts electrical energy into light energy.

4. Efficiency

   • Not all energy is transformed into the intended output like the light bulb over there. It's practically impossible to have a 100% efficient device. But that wasted energy has to go somewhere because energy cannot be created or destroyed .
   • Sankey diagrams are a handy way of setting out energy usage of a device. Here is one for the lightbulb
     • As you can see a lot of energy (90%) is wasted as heat
       • Device efficiency
         • Modern lamps use LEDs for lighting because they are a lot more efficient that filament lamps

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