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BPH702S - BIOMEDICAL PHYSICS - 2ND OPP - JANUARY 2025 |
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p
nAmt BIA UnlVERSITY
OF SCIEnCE AnDTECHnOLOGY
FacultyofHealthN, atural
ResourceasndApplied
Sciences
Schoool f NaturalandApplied
Sciences
Department of Biology,
Chemistryand Physics
B JacksonKaujeuaStreet T: +264612072012
Private Bag13388
F: +264612079012
Windhoek
E: dbcp@nust.na
NAMIBIA
W: www.nust.na
QUALIFICATION : BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BOSC
COURSE: BIOMEDICAL PHYSICS
DATE: JANUARY 2025
DURATION: 3 HOURS
LEVEL: 7
COURSE CODE: BPH702S
SESSION: 1
MARKS: 100
FIRST OPPORTUNITY: EXAMINATION QUESTION PAPER
EXAMINER: Dr Vaino Indongo
MODERATOR: Dr Vera Uushona-Mikka
INSTRUCTIONS:
1. Answer all questions on the separate answer sheet.
2. Please write neatly and legibly.
3. Do not use the left side margin of the exam paper. This must be allowed for the
examiner.
4. No books, notes and other additional aids are allowed.
5. Mark all answers clearly with their respective question numbers.
PERMISSIBLE MATERIAL:
Non-Programmable Calculator
ATTACHEMENT
None
This paper consists of 4 pages including this front page.
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QUESTION 1
[20]
1.1 Briefly explain the terms: (i) mammography, (ii) radiography
(4)
1.2 Study the diagram and answer the questions below.
Stress vs strain of a ligament
250
10.019s, 2301
I
0.015
10.02, 2311
200
. , 271
I 0.012, 192 j 0.018, 2231
g- 150
Ill
Ill
QI
100
so
0
0.005
0.01
0.015
0.02
0.025
Strain (E)
(i) Define, in short, the term strain of a material.
(1)
(ii) Estimate the elastic modulus of a ligament on the Stress-Strain curve?
(3)
(iii) At what strain does the ligament reach its yield strength?
(2)
1.3 List any three types of tissues in the human body.
(3)
1.4 (i) State Graham's law of diffusion.
(2)
(ii) Suppose that the concentration of blood passing through a vein in a human body has a
diffusion constant (D = 1.4 x 10-3 m2/s). The radius and length of the vein are given as 2.3
x 10-3 m and 0.8 m, respectively. Hint: (Ks = 1.3806 x I0-23 m2.kg.s-2.K1, T = 273 K).
What would be the gradient of concentration given that C 1 = 5 x 106 kg/m3 and C2 = 1 x
106 kg/m 3•
(5)
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Biomedical Physics Supplementary/SecondOpportunityExamination Paper, January 2025
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r•
QUESTION2
(20]
2.1 A nozzle with a radius, rn = 20.00 mm was attached to a garden hose ofradius, r11= 4rn. The
flow rate through hose and nozzle is 120.00 Lis.
(i) Calculate the speed of the water in the hose.
(4)
2.2 Derive Bernoulli's equation.
(8)
2.3 Stipulate and discuss the two main essential circuit of the cardiovascular system.
(4)
2.4 Write down an expression of hydrostatic pressure (dp) with respect to depth or height
QUESTION 3
(20]
3.1 Calculate the intensity reflection coefficient, fa, for a fat-liver interface.
Z (fat)= 1.65 x I06 Rayls ; Z (liver)= l.34xl 06 Rayls.
(3)
3.2 Which nuclei produces nuclear magnetic resonance signal used to take an image of a
human body?
(1)
3.3 Determine the total nuclear spins following atoms;
(i) Tritium
(2)
(ii) Sodium (HNa)
(2)
3.4 Mention the time constant which describes the return to equilibrium of the transverse
magnetization, Mxv.
(I)
3.5 A phosphorus sample is at equilibrium in a 1.5 Tesla magnetic field. A constant B1 field
of 2.34xl 0·4 Tesla is applied along the +x'-axis for 17 microseconds. What is the direction
of the net magnetization vector after the B1 field is turned off? [y = 17.25 MHz/1] (5)
3.6 A radiation with a frequency of 3.13 xl0 16 Hz releases an electron from a copper plate. The
kinetic energy of the electron is 2.00 x10· 17J.
Note: Planck's constant, h = 6.63 x 10 - 34 Js, 1 eV = l.602xI0· 19 J.
(i) Calculate the work function (in e V) on the copper plate.
(4)
(ii) Estimate the energy of a photon (in e V) with a frequency of 5.4 x IO14 Hz. (2)
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Biomedical Physics Supplementary/Second Opportunity Examination Paper, January 2025
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QUESTION 4
[20]
4.1 Discuss the effects of increasing voltage on the x-ray tube?
(4)
4.2 Current determines the number of photons the X-ray tube produces and another unit factor
in X-ray quantity is the total exposure time, measured in seconds. The relative output (mAs)
= current (mA) x time (s). Draw a relative output (mAs) vs voltage (keV) diagram showing
peaks of 50, 100 and 150 mAs, with maximum voltage of 100 keVon the X-ray tube. (6)
4.3 An x-ray tube has a beam current of 15 mA and it is operated at a voltage of 40 kV. Note
= that 1 C = 6.25 x 1018 electrons, c 3.0 x 10 8m/ s
(i) Determine the rate at which the machine transforms energy?
(3)
(ii) How many electrons reach the target each second?
(4)
(iii)Determine the wavelength of the photons at an energy of 5.2-x 10- 15 ].
(3)
QUESTION 5
[20]
5.1 Briefly explain the following terms;
(i) Effective dose
(2)
(ii) Half-life of a radionuclide
(2)
(iii)Linear Energy Transfer
(2)
5.2 Give the equation which expresses the Radioactive Decay Law, and explain the meaning
of each of its terms.
(4)
5.3 A radioactive substance consisting of 90,000 particles is found to have a decay constant of
0.0109/day.
(i) What is the half-life of a substance?
(3)
(ii) Determine the activity of the substance.
(3)
5.4 Differentiate malignant and benign tumors
(4)
END!!!!!!
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Biomedical Physics Supplementary/Second Opportunity Examination Paper, January 2025