State what is meant by contrast in an X-ray image.
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
Your answer
Suggested time: 2 min
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9702/04/SP/22 · question 2 of 2 in this topic
Question 10
A parallel beam of X-ray radiation is incident, separately, on samples of bone and of muscle.
Data for the thickness x of the samples of bone and of muscle, together with the linear attenuation coefficients μ of the radiation in bone and in muscle, are given in Table 10.1: bone x = 1.5 cm, μ = 2.9 cm⁻¹; muscle x = 4.0 cm, μ = 0.95 cm⁻¹.
Calculate the ratio (intensity of radiation transmitted through the bone) / (intensity of radiation transmitted through the muscle).
Calculate Show your working. The method can earn marks even when the final value is wrong, and a bare answer often cannot.
Your answer
Suggested time: 3 min
Explain how ultrasound pulses are used to obtain diagnostic information about internal body structures in medical diagnosis.
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
Your answer
Suggested time: 5 min
Two media have specific acoustic impedances Z₁ and Z₂.
State the approximate value of the intensity reflection coefficient at the boundary between the two media when:
• Z₁ is almost equal to Z₂
• Z₁ is very different from Z₂.
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
Your answer
Suggested time: 3 min
9702/04/SP/22Cambridge International AS & A Level Physics 9702 · Specimen 2022 · Paper 4 · sit the whole paper