Applications of Radiation in everyday Life :

1. Appliances which need to store heat are generally highly polished. E.g. Kettles, Saucepans

2. When the heat is required to be kept out, bright colors are used.

In tropical countries houses are generally painted with bright colors. ˆ Refrigerators are painted while and oil tanks are painted with alu- minum paint, while the back side of the refrigerators and hot plates are painted with dull black color. ˆ We wear generally while or light colored clothes during summers while in winter we wear dark coloured clothes.

3. It heat is required to be lost fast, appliances are painted with black or dull colors, e.g. Car radiators and fluid pipes behind refrigerators.

Thermos Flask

• Invented by Sir James Dewar

​Reduction of heat transfer in a Thermos flask :

• Use of glass for container, cork for stopper and plastic for cap minimizes the heat transfer by conduction.
• Use of vacuum in between the double walled glass container, prevents heat transfer not only by conduction but also by convection.
• Silvering of glass walls from inside (vacuum side) reduces appreciably the heat transfer by radiation. Silvering of glass walls reflect back most of the heat radiation.