In-Class Questions

1. Why aren't $^{16}$O, $^{12}$C, or $^{40}$Ca used in MRI?

   No free proton to generate magnetic moment.
   
   
   
   
   
   
   

2. What is the magnetic charge of the proton? Of any System?

   Zero. No magnetic monopoles have been observed.
   
   
   
   
   
   
   

3. For a gyroscope with spin in the same direction as $\vec{\mu}$ in the notes, why is its precession counterclockwise?

   gravity is in the opposite direction of the magnetic field.
   
   
   
   
   
   
   

4. Current clinical standard field is 1.5T. If a 1H proton is in this field, what frequency will it be precessing at? Is this frequency closest to the frequency of gamma particles, radio, microwave, X-Ray, cosmic rays?

   Approximately 64MHz, radio
   
   
   
   
   
   
   

5. At 1.5T what is the precession frequency for an electron? What radiation is this frequency closest to? If two electrons see a field difference of 1.0E-6T what will be the difference in Hz between their resonant frequencies?

   Approximately 64,000 MHz, microwave, 42kHz
   
   
   
   
   
   
   

HWS 3.3 3.4 3.6 4.1 4.5 4.6