500 nm corresponds to green light. QUESTION: Which of the following wavelengths is associated with electromagnetic radiation that humans can see? A. 500 nm, B. 300 nm, C. 0.0005 cm Electromagnetic radiation that humans can see: 400 to 800 nm (the “visible spectrum”) 500 nm corresponds to green light. Other choices are invisible: 300 nm < 400 nm; Since 1 nm = 10-9 m: 0.0005 cm = 500,000 nm SCRIPT: Which of the following wavelengths is associated with electromagnetic radiation that humans can see? A. 500 nm, B. 0.1 cm, C. 300 nm, D. 0.0005 cm PAUSE CLICK For us to be able to see electromagnetic radiation, its wavelength must be between 400 and 800 nanometers. This is known as the visible spectrum. Of the choices given, only A is obviously between 400 and 800 nanometers. In fact, 500 nanometers corresponds to light that our eyes perceives as green. Note that sequence of colors in the spectrum is the same sequence you see in a rainbow. ROYGBIV. Red orange yellow green blue indigo violet. The long wavelength end is red, and the short wavelength end is violet. The other choices given here are invisible to us. 300 nanometers is less than 400 nanometers; it’s in what we call the ultraviolet or UV region of the electromagnetic spectrum. CALLOUT “Ultraviolet” pointing to 300 nm Since a nanometer is ten to the negative nine meters, 0.0005 centimeters is equivalent to 500,000 nanometers. This would be longer than 800 nanometers. In fact, this wavelength falls in what we call the infrared or IR region of the electromagnetic spectrum. PAUSE CLICK END RECORDING

Video ID: 2-1-2 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08