1. Define or otherwise identify the following:
   • Photon
   • Radiolucency
   • Inverse square law
   • Frequency
   • Law of conservation of energy
   • Gamma ray
   • Electromagnetic spectrum
   • Sinusoidal variation
   • Visible light
2. Write the wave equation.
3. How are frequency and wavelength related?
4. What is the energy range of diagnostic x-rays?
5. What is the difference between x-rays and gamma rays?
6. What is attenuation?
7. What is the range in intensity of the earth's magnetic field?
8. Explain how a magnetic domain can cause an object to behave like a magnet.