GATE 2025 BM – Question 43
Which statements about ultrasound are true?
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Correct answer: (A) Acoustic impedance is directly proportional to tissue density; (B) Reflection coefficient depends on impedance mismatch at a tissue interface
Explanation
Specific acoustic impedance is Z=ρc, hence proportional to density for a fixed propagation speed, the relationship intended in A. At normal incidence, reflected energy fraction is [(Z2−Z1)/(Z2+Z1)]², proving B and refuting C,D. Thus A,B, with sound speed also relevant when comparing different tissues.