DP Physics (last assessment 2024)
Question 19M.3.HL.TZ1.16b
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.HL.TZ1.16b |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Explain | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
19M.3.HL.TZ1.16b
(b)
The fluid in the bowel has a similar linear attenuation coefficient as the bowel surface. Gases have much lower linear attenuation coefficients than fluids. Explain why doctors will fill the bowel with air before taking an X-ray image.
[2]
Markscheme
to produce an X-ray image there must be constrast/a difference in the intensity of the beam transmitted through tissue and the bowel ✔
introduction of air will produce contrast ✔
Examiners report
In (b) only the best candidates well identified the importance of the change in contrast of the image (resulting from different attenuation values) needed to locate the organ.
