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Unformatted text preview: ANSWERS!!! 1. a. What is E (the resonance energy) for 1 H? for 13 C? for 15 N in a 9.4T magnet? ( 1H = , 13C = , 15N = ) 1 H: 4.22 10-26 joules, 13 C: 1.06 10-26 joules, 15 N: 4.28 10-27 joules b. What does this imply about the signal strength for each nucleus? The smaller the E, the smaller the population difference between the two states and the smaller the signal. 2. What sampling rate would you need to fully characterize a spectrum ranging from 0 - 10 ppm on a 500 MHz spectrometer? 0.0002 sec = t = 1/(2 v N ) where v N = (10-0)ppm*500MHz/2 3. Explain why exponential multiplication of a FID can increase S/N or resolution, but not both simultaneously. An increasing exponential will increase resolution by emphasizing the middle portion of the FID and artificially increased T 2 . It also slightly increases the noise and decreases the signal. A decreasing exponential emphasizes the first points of the FID which increase the signal, and minimizes the noise. It causes an artificially decreased T...
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- Fall '09