College Physics MRI’s EPCC
Show your work on a separate document. Block or highlight your answers. Limit your
esponses to within 3 sentences. Use your own sketches to help illustrate your
esponse if needed.
1. Refer to figure 1. A hydrogen proton is aligned to an MRI’s magnetic field of 1.50 T. If
this proton’s (i.e. hydrogen atom) has a magnetic moment of 1.86x10-23 N·mT-1,
calculate the torque it experiences when a radio wave perpendicular to the spin
orientation re-aligns the proton to spin 90.0° to the MRI’s magnetic field.
2. A sample of magnetotactic bacteria known as Magnetospirillum magneticum AMB-1, a
member of the Magnetospirillum genus, incorporate Iron Oxide (Fe3O4) in their
magnetosomes (a type of organelle) for Magneto-aerotaxis; the ability for the bacteria
to move through a magnetic field. These magnetosomes are used to help locate
sources of oxygen within its environment. The premise is that the higher magnetic
moment associated with the amount of Fe3O4 in these magnetosomes allows for better
detection of oxygen. The table below has the magnetic moments of hypothetical
sample of Magnetospirillum magneticum. Calculate the maximum torque these
acterium would experience in a 3.50 T magnetic field and record your results in table.
Which case would the bacterium yield the best chance to detect oxygen?
Table 1. Magnetic moments of magnetosomes.
Iron concentration (μM) Magnetic moment XXXXXXXXXXAm2 ) Torque (N●m)
5 30
30 90
100 100
Abstract link: https:
www.sciencedirect.com/science/article/pii/S XXXXXXXXXX
Figure 1: Image depicting the interaction of a magnetic field on a sample.
Photo credit: NIH
https:
www.sciencedirect.com/science/article/pii/S XXXXXXXXXX