Question 1 1) Why do you think MRI machines are designed for the pulse frequency to enter in resonance specifically withHydrogen atoms? What other elements could theoretically work other than Hydrogen?2) Gasoline-Electric hybrid vehicles like the Toyota Prius, have both electric and gasoline motors. How is thebattery of the car charged if the car does not have a charging port? Hint: one component serves a dual purpose.3) As discussed in class some birds and microorganisms have a "magnetic" spatial sense. This means there aretraces of certain elements on some partstheir nervous systems. Which of these elements could be? Which isthe most likely one?4) The instruments that measure rotational speed (RPM's)of a machine like cars are called Tachometers, and canSquaring CircuitPhoto Sensorbe constructed with magnetic sensors or light sensorsDiskthat measure a number of revolutions per minute. IsLEDone approach better than the other? Comment on theadvantages of optical vs magnetic rotational sensorsMagnetRotating ShaftMagnetic Sensor

Magnetic resonance imaging (MRI) produces the most detailed images of the patient's internal blood vessels, bones, nerves, and any organ. MRI imaging is a powerful diagnostic tool based on the magnetic property of the hydrogen nucleus. MRI machines are designed to sense nuclear spin precession of hydrogen nuclei around the axis along the direction of the applied magnetic field. MRI machine uses a strong magnetic field, however, without any adverse effects on the human body. MRI machines are designed to sense hydrogen atoms due to the abundance of hydrogen in the body. The abundance of hydrogen is attributed to water. Water is a universal solvent or rather solvent of life, so it appears in most of the organs. Furthermore, hydrogen is also part of the fat or oily regions of the body. Therefore, for all practical reasons, there is no better alternative to hydrogen atom-based MRI imaging. To address the next part of the question, i.e., why do MRI machines operate in the pulse mode? The pulse mode of operation has nothing to do with the strength of the magnetic field, but rather is aimed at obtaining high contrast images. The image contrast is a result of differences in the strength of the nuclear magnetic resonance signal recovered from different locations of the body. The key factors that affect image contrast are as follows: (a) relative density of the excited nuclei (thus, hydrogen atom). (b) differences in the nuclear spin relaxation times (there are three different times say T1, T2, and T*) The second factor (b) can be used to enhance contrast by carefully designing the pulse mode of the MRI machine. Therefore, it is the image contrast that dictates the pulsed mode of operation and the choice for the hydrogen atom. Based on the above discussion, perhaps there is no better alternative for the hydrogen atom. Another abundant atom in our body is carbon. However, C12, the most prevalent carbon isotope has no unpaired neutrons or protons, rendering it unsuitable. However, C12 has an isotope C13, which could be magnetically active but again this isotope occurs in trace quantity. Thus, C13 couldn't be an alternative.

Answered: 1) Why do you think MRI machines are…

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1) Why do you think MRI machines are designed for the pulse frequency to enter in resonance specifically with Hydrogen atoms? What other elements could theoretically work other than Hydrogen?