A "pulse oximeter operates by using light and a photocell to measure oxygen saturation in arterial blood. The transmission of light energy as it passes through a solution of light-absorbing molecules is described by the Beer-Lambert law
which gives the decrease in intensity I in terms of the distance L the light has traveled through a fluid with a concentration C of the light-absorbing molecule. The quantity ε is called the extinction coefficient, and its value depends on the frequency of the light. (It has units of m2/mol) Assume the extinction coefficient for 660-nm light passing through a solution of oxygenated hemoglobin is identical to the coefficient for 940-nm light passing through deoxygenated hemoglobin. Also assume that 940-nm light has zero absorption (ε=0) in oxygenated hemoglobin and 660-nm light has zero absorption in deoxygenated hemoglobin. If 32.2% of the energy of the red source and 77.9% of the infrared energy is transmitted through the blood, what is the fraction of hemoglobin that is oxygenated?
A "pulse oximeter operates by using light and a photocell to measure oxygen saturation in arterial blood
Oxygenated hemoglobin absorbs weakly in the red (hence its red color) and strongly in the near infrared, whereas deoxygenated hemoglobin has the opposite absorption. This fact is used in a "pulse oximeter" to measure oxygen saturation in arterial blood. The device clips onto the end of a person's finger and has two light-emitting diodes—a red (653 nm) and an infrared (906 nm)—and a photocell that detects the amount of light transmitted through the finger at each wavelength. (a) Determine the...
> Do the log of the decimal from the percentage divided by 100 instead of the actual percentage and that should get you the right answer.
mochi12 Mon, Mar 7, 2022 12:07 PM