http://www.ck12.org Chapter 13. Light
Summary
- We see objects because they either generate or reflect light, which then enters our eyes.
- Visible light is a small fraction of the energy we call electromagnetic radiation.
- Electromagnetic radiation is a form of energy that consists of oscillating electric and magnetic fields traveling
at the speed of light. - The energy of an electromagnetic wave travels in a straight line along the path of the wave.
- In a vacuum, every electromagnetic wave has a velocity of 3. 00 × 108 m/s, which is symbolized by the lower
casec. - The relationship of velocity, wavelength, and frequency of electromagnetic waves is:c=λf.
- Light that has all its field oscillations in the same direction is said to be polarized.
Practice
Questions
Use the video on the visible light spectrum to answer the questions that follow.
http://video.about.com/physics/The-Visible-Light-Spectrum.htm
- What wavelengths are included in the visible spectrum?
- All colors of light mixed together produces _____.
- What is necessary for a rainbow to form?
Review
Questions
- Sound doesn’t travel through a vacuum because there are no molecules to carry it. How do we know that light
does travel through a vacuum? - What is the range of wavelength of electromagnetic radiation the human eye can detect?