<prompt> Modern monitors to measure ETCO2 make use ofInfrared absorption spectroscopyUltra violet raysLaser technologyScatter technology  <response>: Measurements of variations in the respiratory cycle of expired carbon dioxide by displayed waveform and by absolute numerical values is defined as Capnography and Capnometry respectivelyMeasurement of the exhaled CO2 at the level of upper airway at the end of expiration when CO2 is at its maximum is referred to as 3end tidal CO2 EtCO2Modern monitors used to measure EtCO2 in the exhaled air make use of infrared absorption spectroscopyRefer: Morgan and Mikhails Clinical Anaesthesiology, 5th edition, pg no. 126 