GATE-2018 (24) :Wyllie – Time average equation

GATE

37. The Larmor precession frequency (in HZ) measured by proton precession magnetometer for a total field of 50,000 nT is ( gyromagnetic ratio of proton rp=0.267513 nT^-1 S^-1)

A) 1890                          B) 2020                             C) 2130                         D) 2420

Solution:

In proton- precession magnetometer, the realtion between larmor 

precession frequency and the total field is

f= (γ_p* B_t) / (2*π) -----------------(1)

B_t – total magnetic field

γ_p- gyromagnetic ratio of proton

f- larmor precession frequency

substitute above values in eq(1)

f= (0.267513 * 50,000) / (2*3.14)

f= 13,375.65 / 6.28

f= 2,129.88 Hz