need help for this question. Thank you. A motorised syringe is designed to admin
ID: 2083766 • Letter: N
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need help for this question. Thank you.
A motorised syringe is designed to administer intravenous medication in a highly controlled manner, by slowly pumping fluids using a linear motion of the syringe handle over a maximum range of 5cm. For medical x-ray imaging experiments performed at a synchrotron, the digital readout from the syringe system ceases to work, due to an electrical malfunction, yet the motor still functions correctly. Scientists cannot stand and watch the syringe markers when the x-ray beam is on, due to safety concerns, yet the liquid dose needs to be measured as a function of time. Trial fixes with mobile phone cameras and webcams were found to be inaccurate. With limited access time for the x-ray beam soon running out, you quickly build an apparatus that ought to work using two transparent plastic rules, each with opaque millimetre markings. One ruler is fastened to the moving syringe handle and the other ruler is fastened to a stand on the supporting bench. With one ruler sliding against the other in a parallel motion, a light emitting diode (LED) of 3.0 mW total power output is shone through the overlapping m metre markings and a digital power meter records the oscillating integrated intensity to a computer. The LED emits red light of uniform intensity from its square 3.0mm times 3.0mm flat face. There are no other visible light sources in the experiment (the room is completely dark if the LED is off). One of the rulers and other apparatus are drawn to scale in figure 1. Read the caption carefully. Figure 1: Light emitting diode adjacent to a transparent plastic ruler, with a power meter covered in a makeshift aluminium foil mask, designed to block all but one square window of size 1.0mm times 1.0mm. The ruler tick-marks are each 0.2mm wide. A 2nd ruler is not shown. In two sentences, describe how this quick fix might work to measure the linear displacement of the syringe handle as a function of time. The mask on the power meter is symmetrically placed between two of the tick marks of the non-moving ruler that is fixed to the bench stand. The aluminium foil touches the bottom of the ruler and the mask is symmetrically aligned with the tick marks. If the motor supplies a linear displacement of 1.0mm per second, plot a graph which models the measured power as a function of time. Be sure to indicate calibrated axes with appropriate labels and units. Also state the maximum and minimum power readings, the shortest time interval between these readings and the frequency with which intensity maxima are successively recorded. One scientist in the collaborative team complains that the aluminum foil was not folded accurately, with more important concerns that the other ruler may have gently scraped and displaced the foil over time as it moved with the syringe above the fixed ruler. In two sentences, explain whether the measurements could be reliably carried out with the foil removed and what might be different in that scenario.Explanation / Answer
When one ruler moves with respect to the fied ruler, the intensity of light blocked by the opaque millimeter reading will rise and ebb alternately. The number of times one sinusoid completes is the number of millimeters displaced by the syringe.
Since the mask is 1mm wide, and 0.2mm of the mask will be covered in the opaque marking, when the two rulers coincide, and 0.4mm of it will be covered with they dont coincide.
For the entire area of LED: 9 mm^2, 3mW of light energy is emmitted
For area of the mask: 1mm^2, (1/3)mW of light energy is received
For the area od mask considering the opaque tickmarks - when the rulers co-incide: 0.64mm^2, (0.64/3) mW of light energy is received,
For the area od mask considering the opaque tickmarks - when the rulers do not coincide: 0.36mm^2, (0.36/3) mW of light energy is received
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