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 (660. nm) and an infrared (940. nm)—and a photocell that detects the amount of light transmitted through the linger at each wavelength. (a) Determine the frequency of each of these light sources. (b) If 67% of the energy of the red source is absorbed in the blood, by what factor does the amplitude of the
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Chapter 21 Solutions
College Physics
- 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 (635 nm) and an infrared (935 nm) -and a photocell that detects the amount of light transmitted through the finger at each wavelength. (a) Determine the frequency of each of these light sources. red Hz infrared Hz (b) If 63% of the energy of the red source is absorbed in the blood, by what factor does the amplitude of the electromagnetic wave change? Hint: The intensity of the wave is equal to the average power per unit area as given by 2 E max I = -B, 2H0 2. maxarrow_forwardQuestion 2: a. Find DC resistance of a diode, if voltage applied across a Silicon diode at room temperature (300° K) is (7/100) V. Saturation current, at this temperature is (7×10-2)A. Consider n = 2 for Silicon diode and VT = 26 mV. b. Let an emf of (32) V is induced from a coil when the alternating current changes at the rate of (257) Ampere per second. Find the following: i. Inductance of the coil, and ii. Energy stored in the coil.arrow_forwardOxygenated 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 (659 nm) and an infrared (979 nm)-and a photocell that detects the amount of light transmitted through the finger at each wavelength. (a) Determine the frequency of each of these light sources. red Hz infrared Hz (b) If 63% of the energy of the red source is absorbed in the blood, by what factor does the amplitude of the electromagnetic wave change? Hint: The intensity of the wave is equal to the average power per unit area as given by 2 E 2 -Bmay?. 240 I = max max Need Help? Read Itarrow_forward
- A citizen’s band radio transmitter operates at a frequency of 27.1 MHz. The peak voltage across the transmitter is 10-V. Write an expression for the variation of voltage with time. What is the time for one cycle? use the formula V=Vo sin (2πft)arrow_forwardA capacitor, C'is connected across an emf given by: v(t) = Vo sin(wt) Write an expression for the current through the capacitor. I(t) =arrow_forwardA citizen’s band radio transmitter operates at a frequency of 27.1 MHz. The peak voltage across the transmitter is 10-V. Write an expression for the variation of voltage with time. What is the time for one cycle?arrow_forward
- State the types of resistor colour band in use and hence determine the colours of the following resistors: (i) M56±1%; (ii) 120K±2% (iii) 8R8±10%arrow_forwardWhat would be the depth of penetration for copper at 5 MHz frequency with o = 5.8 x 10'? 29.56 µm 38.162 µm 66.1 µm 33.05 µmarrow_forwardWhen an electric current is maintained in an electrolytic cell of slightly acidic water and 1 mole of water is electrolyzed in to hydrogen and oxygen, two faradays of charge are transferred through a source of emf (E). The energy change of the system is +286500 J and 50,000 J of heat is absorbed. Calculate the emf (E) ? Given 1 Faraday = 96500 C/mol.?arrow_forward
- An UV sensor collects the altitude, battery level, speed data that are being sent using TDM. Each UV sensor sends a Four-bit data packet at a time. Assume that the first three data packets from each sensor are shown in the table below, show the data stream in binary on the channel by using synchronization Time 2 13 (1101) 9 (1001) 7 (0111) Time 3 10 (1010) 8 (1000) 12 (1100) Time 1 Altitude (m) - Sensorl Battery level (*10%) – Sensor 2 bits Speed (m/s) – Sensor 3 15 (1111) 9 (1001) 7 (0111)arrow_forwardo 20 V Determine а. VG b. Ipq and VGsQ С. Vр апd Vs d. VpsQ 2.2 k2 910 k2 D Ipss = 10 mA Vp =-3.5 V Vase 110 k2 1.1 k2arrow_forwardFor the given circuit with current, voltages across elements shown below. For R = 18 Ohm, L=12.4 Henry, C=16.5 Farad and v, (t)=e3t + sin(2t) volt, Find a) It(s) V2(s) b) Vi(s) R v (t) 3 ? (1) C v,(t) e Vr. lellarrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning