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Information about the location of the hydrogen atoms can be obtained by adding a calibrated gradient field across the region of the sample. With an increasing magnetic field as you move to the right across the sample, the spin-flip energy and therefore the frequency of the emitted signal increases from left to right. When excited by an RF transmitter, the emitted signal contains different frequencies for the two proton concentration areas. These frequencies can be separated by means of the Fourier transform and the example gives two different regions of frequency for the two sample areas. This is the beginning of the process of locating the hydrogen atoms.
Problem :
Essential University Physics Volume 2
Chapter 38 Problem 38:
An NMR spectrometer is described as a “300-MHz instrument,” meaning 300 MHz is the frequency supplied to its transmitter coil to flip the spin states of bare protons. What’s the strength of its unperturbed magnetic field?
Solution: 