1.Infrared radiation is also called IR. Describe how it is different from visible light.What emits IR? Can animals use it? Explain how emission of IR sometimes "wastes"energy. Give examples showing how IR ia used in modern technology.

2.Modern medical imaging can do much more than take a simple x-ray.Define and explain four methods methods that are used for medical imaging .Explain the physic behind the techniques, describe what they measure, and say something about the application

3.Visible light is an electromagnectic wave. Name five other phenomena that are also electrimagnetic waves but have different name.How do these waves differ? Briefly describe application for each of these waves.

4. Human have been polluting the atmosphere in ways that could have lasting effect for future generation.What are the chemical that have been put into the air that could do this ? What effects could they have? Describe as much of the relevant physics as you can .