Lab: Blackbody Spectrum Simulation
Travis Vermeer Blackbody Radiation
Go to http://phet.colorado.edu/simulations/sims.php?sim=Blackbody_Spectrum and click on Run Now.
1) In this lab, you will use the Blackbody Spectrum Simulation to investigate how the spectrum of electromagnetic radiation emitted by objects is affected by the object's temperature. In this simulation, you can input the temperature and observe the spectrum of the radiation emitted. a) The temperature of stars in the universe varies with the type of star and the age of the star among other things. By looking at the shape of the spectrum of light emitted by a star, we can tell something about its average surface temperature. i) If we observe a star's spectrum and find that the peak power occurs at the border between red and infrared light, what is the approximate surface temperature of the star? (in degrees C) - The approximate temperature would be 3767 degrees C
ii) If we observe a stars spectrum and find that the peak power occurs at the border between blue and ultraviolet light, what is the surface temperature of the star? (in degrees C) - The temperature of the star would be 6827 degrees C
b) Light bulbs operate at 2500 degrees C. i) What is the wavelength at which the most power is emitted for a light bulb operating at 2500 C? - 2500+273.15=2773K peak power at 1050nm
ii) Explain why regular incandescent bulbs waste a lot of energy. Be sure to include your reasoning. - Because only about 12% of the energy goes into producing visible light. Much of the energy input is in a wavelength that is not visible, thus it is wasted.
c) Use the Spectrum Simulation to investigate changes in the amount of light at visible wavelengths due to this change in temperature from 2500 C to 2000 C. i) What is the approximate ratio between the powers emitted at 500 nm at 2000 degrees C to that at 2500 degrees C, that
Go to http://phet.colorado.edu/simulations/sims.php?sim=Blackbody_Spectrum and click on Run Now.
1) In this lab, you will use the Blackbody Spectrum Simulation to investigate how the spectrum of electromagnetic radiation emitted by objects is affected by the object's temperature. In this simulation, you can input the temperature and observe the spectrum of the radiation emitted. a) The temperature of stars in the universe varies with the type of star and the age of the star among other things. By looking at the shape of the spectrum of light emitted by a star, we can tell something about its average surface temperature. i) If we observe a star's spectrum and find that the peak power occurs at the border between red and infrared light, what is the approximate surface temperature of the star? (in degrees C) - The approximate temperature would be 3767 degrees C
ii) If we observe a stars spectrum and find that the peak power occurs at the border between blue and ultraviolet light, what is the surface temperature of the star? (in degrees C) - The temperature of the star would be 6827 degrees C
b) Light bulbs operate at 2500 degrees C. i) What is the wavelength at which the most power is emitted for a light bulb operating at 2500 C? - 2500+273.15=2773K peak power at 1050nm
ii) Explain why regular incandescent bulbs waste a lot of energy. Be sure to include your reasoning. - Because only about 12% of the energy goes into producing visible light. Much of the energy input is in a wavelength that is not visible, thus it is wasted.
c) Use the Spectrum Simulation to investigate changes in the amount of light at visible wavelengths due to this change in temperature from 2500 C to 2000 C. i) What is the approximate ratio between the powers emitted at 500 nm at 2000 degrees C to that at 2500 degrees C, that