Shielded Protons electrons shielding effective effective field field 70.458 70.459 300 MHz ●300MHz 300MH7 absorbs does not absorbs absorb Bo Bo Bo 70.459 gauss 70.459 gauss 70,460 gauss naked proton shielded proton stronger applied field absorbs at 70,459 G feels less than 70,459 G compensates for shielding A naked proton will absorb at 70,459 gauss A shielded proton will not absorb at 70,459 gauss so the magnetic field must be increased slightly to achieve resonance. 2013 Pearson Education,Inc. Chapter 13 © 2013 Pearson Education, Inc. Chapter 13 12 Shielded Protons • A naked proton will absorb at 70,459 gauss. • A shielded proton will not absorb at 70,459 gauss so the magnetic field must be increased slightly to achieve resonance