Physics · 2001 · May · Paper 3 · HL · Markscheme

MARKSCHEME May 2001 PHYSICS Higher Level Paper 3 20 pages M01/430/H(3)M INTERNATIONAL BACCALAUREATE BACCALAURÉAT INTERNATIONAL BACHILLERATO INTERNACIONAL OPTION D – BIOMEDICAL PHYSICS [1] [1] [2 max] D1. (a) systolic: maximum blood pressure produced by a heartbeat; diastolic: the pressure when the heart relaxes between beats; (award [1] for just maximum and minimum. For [2] some reference should be made to the heart beating. Something like ‘the pressure of the blood leaving the heart and the pressure of the blood returning to the heart’ would be OK;) [1](b) recognise that ; pg hρ= [1] [2 max] correct substitution to give Pa; 41.1 10× (c) the upper arm is at nearly the same level as the heart; [1] hence hydrostatic pressure will not effect the reading; [1] i.e. the reading will be equal to that of the pressure at the heart; [2 max] (d) estimated height of aorta above the ankle = 1.2 m (allow 1 m to 1.6 m); [1] hydrostatic pressure difference Dp = 1000 % 10 % 1.2 Pa = 90 mm of Hg; [1] pressure reading at ankle = 90 + 140 = 230 mm of Hg (138 to 254); [1] answer in kPa acceptable = 32 kPa (19 to 35); assumptions: ignore any pressure drops due to fluid flow resistance; [1] assume blood has same density as water; [1] [4 max] [1] [1] [1] [1] D2. (a) energy loss is proportional to surface area; mass is proportional to volume; () () 3 3 17 ;5 1 tobytoby susie susie M M == 2 2 2 31 7 1.25;51 toby susie == (accept Susie to Toby = 0.8 but deduct [1] if this is not made clear;) [4 max] (b) any sensible assumption; e.g. same build i.e. same overall shape, identical clothing; [1 max] – 6 – M01/430/H(3)M