1Why are radio waves considered safe to use? Write their uses.
2How does a microwave oven cook food?
3How are microwaves used in radar? Give two examples.
4What does the word infrared mean? Write any three uses of infrared waves.
5Why does a green leaf look green to us?
6What is the SODIS method? How is water purified by it?
7Write any four uses of X-rays.
8What is radiotherapy? Why must gamma rays be used only in a controlled way?
9Name the electromagnetic wave used in each of these jobs: air traffic control, night surveillance, making vitamin D in the skin, sterilising surgical equipment.