A spin system is excited by a 180% - 1- 90 sequence (this sequence means that at t=0, a 180 degree pulse is applied with B; along x* . then after a delay of time intervissueal t, a 90 degree pulse 1s applied with B, along X ). (a) plot the time evolution of the M. component in the t tume mterval. (b) calculate the magmtude of M, immediately after the 90 pulse : (c) in one study, the goal is to suppress the signal from white matter. Find t so that the magnitude of My in white matter immediately after the 90% pulse is zero. Will the signal from CSF also be zero for the same pulse sequence? Tissue type Relalwe White Matter - Cerebrospina 1.00 I fluid (CSF)