=c/; Lower frequency

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Presentation transcript:

=c/; Lower frequency QUESTION: Which of the following regions of the electromagnetic spectrum has the most energetic photons? A. x-rays, B. visible, C. microwave, D. radiowave Electromagnetic radiation that humans can see: 400 to 800 nm (the “visible spectrum”) x-rays, ultraviolet infrared, microwave, radiowave ; Longer wavelength SCRIPT: Which of the following regions of the electromagnetic spectrum has the longest wavelengths? A. x-rays, B. visible, C. microwave, D. radiowave 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. Electromagnetic radiation that we perceive as violet is at the short wavelength end of the visible spectrum Red light is at the long wavelength end of the spectrum The term electromagnetic spectrum refers to the entire range of possible wavelengths. The electromagnetic spectrum is divided into several regions. Wavelengths shorter than violet belong to the ultraviolet and x-ray regions. X-rays have shorter wavelengths than ultraviolet radiation. CLICK Wavelengths longer than that of red light belong to the infrared, microwave, and radiowave regions. Ih other wods, for the types of electromagnetic radiation shown here, x rays have the shortest wavelengths, and radiowaves have the longest wavelengths. The frequency of electromagnetic radiation, often represented by the letter nu HIGHLIGHT is related to the wavelength by the equation by this equation. HIGHLIGHT The frequency is equal to the speed of light, which is customarily represented by the letter c… CALLOUT Divided by the wavelength, which is customarily represented by the green letter lambda This equation tells us that… the longer the wavelength,…the lower the frequency. The longer the cycle is, the fewer cycles can pass through a given point per unit time. If you divide c by a bigger number, you get a smaller number. IN other words, of the types of radiation listed here, x-rays have the highest frequency… and radiowaves have the lowest frequencies. As for photon energies,… They are proportional to the frequency. The energy of a photon is equal to a h times the frequency nu. H is a constant, … Planck’s constant. CALLOUT “Planck’s constant” The higher the frequency… the higher the photon energy. This means that x rays have the most energetic photons…. And radiowaves have the least energetic photons. The correct answer is A. PAUSE CLICK END RECORDING =c/; Lower frequency E=h; Less energetic photons

Video ID: 2-1-6 © 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