Medical Physics
Definitions: Medical Physics
Exam question
Define specific acoustic impedance.
9702/41 · Oct/Nov 2025 · Q10(a)
Model answer
The product of the density of the medium and the speed of sound in that medium.
Exam question
State what is meant by the attenuation of an ultrasound wave.
9702/41 · May/Jun 2020 · Q4(b)(i)
Model answer
A reduction in the intensity of the ultrasound wave as it passes through a medium.
Exam question
State what is meant by contrast in an X-ray image.
9702/42 · Oct/Nov 2025 · Q10(a)
Model answer
The difference in degrees of blackening between regions of the image.
Exam question
State what is meant by a tracer.
9702/42 · Oct/Nov 2023 · Q9(a)(i)
Model answer
A material introduced into the body whose position can be detected.
Exam question
Explain what is meant by annihilation.
9702/42 · Feb/Mar 2022 · Q11(b)(i)
Model answer
A particle interacts with its antiparticle so that their mass is converted into energy.