Using a Remote Control to Determine the Infrared Absorption Coefficient in Water

• Santiago Ortuño-Molina ^[1] ; Adrián Garmendía-Martínez ^[1] ; Francisco M. Muñoz-Pérez ^[1] ; Juan C. Castro-Palacio ^[1] ; Juan A. Monsoriu ^[1]
  1. [1] Universidad Politécnica de Valencia

     Universidad Politécnica de Valencia

     Valencia, España

     
• Localización: The Physics Teacher, ISSN 0031-921X, Vol. 63, Nº. 9, 2025, págs. 776-778
• Idioma: inglés
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• Resumen

  • In this work, we present a simple and low-cost experiment designed to determine the infrared water absorption coefficient. We used a TV remote control as a point source of infrared light. The intensity after passing the light through different heights of a water column is measured with a solar cell connected to a speaker. The recorded signal, captured with a smartphone sound recorder, provides a practical demonstration of the Beer–Lambert law. The collected data were fitted to the theoretical model, obtaining a very good agreement between the value of the water absorption coefficient obtained experimentally and that reported in the literature.