The frequency 
of the electromagnetic waves emitted by protons on relaxation in an MR scanner is given by the equation
where 
is the total magnetic flux density and 
is a constant equal to 
. The magnetic flux density changes by 
for each 
thickness of tissue in a section. The scanner is adjusted so that the thickness of each section is 
. Calculate, for corresponding points in neighbouring sections,
the difference in magnetic flux density
the change in emitted frequency.
.
.
