efficiency

• how can the efficiency of a mechanical machine with moving parts be improved?

  lubricate any moving parts to reduce friction and therefore energy loss due to heating

  
• transformers have high

  efficiency

  
• how can the efficiency of a radiator be improved

  installing metal foil sheets to reflect the heat back into the room rather than it being absorbed by the walls.

  
• how can the efficiency of boiling water in a pan be improved

  by placing a lid on the pan to reduce the heat loss from the top.