A modification to a digital lux meter is described. A Malus’ law experiment performed with the meter gives unexpected results. The modified meter is used to show that the unexpected findings result from the inability of Polaroid filters to polarize radiation that is outside the range of visible light. With the use of a diffraction grating and the modified meter crossed Polaroids are shown to transmit infrared radiation.

Topics
Infrared radiation, Gratings, Optical polarization, Optical properties
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© 2001 American Association of Physics Teachers.
2001
American Association of Physics Teachers
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