How could you improve the energy efficiency of a kettle?Watch
-You want to think about two things in particular: what will help it to absorb as much heat as possible, and what will help it to retain that heat? Plus the safety features.
-Think about the shiny surface of a kettle. What do shiny surfaces do by way of radiation?
-Think about the black, plastic handle(this is a safety feature). How does its colour and the fact that it is plastic help to prevent our hands from burning?
- It might be a bit less obvious, but if the kettle is made from a shiny substance other than metal, how would this help( btw this is often the case with modern kettles)?
In questions like these, you need to think about the purpose of the item, its design, and often its safety features. Take into account all three of: conduction, convection and radiation.
Hope that helps