1. The document discusses various properties of light including its speed, wavelength, frequency, and energy as it relates to different types of electromagnetic radiation such as x-rays, radio waves, and visible light. 2. Key concepts around the behavior of light are covered like reflection, refraction, and how light interacts with lenses to cause vision corrections for nearsightedness and farsightedness. 3. The particle-wave duality of light is examined through experiments like the photoelectric effect which provided evidence that light behaves as quantized packets of energy called photons.