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BPH702S - BIOMEDICAL PHYSICS - 2ND OPP - JANUARY 2024 |
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1V~11nAmlBIA UnlVERSITY
OF sc1EncE AnoTECHnOLOGY
FacultyofHealthN, atural
ResourceasndApplied
Sciences
Schoolof NaturalandApplied
Sciences
Departmentof Biology,
Chemistryand Physics
13JacksonKaujeuaStreet T: +264612072012
Private Bag13388
F: +264612079012
Windhoek
E: dbcp@nust.na
NAMIBIA
W: www.nust.na
QUALIFICATION: BACHELOR OF SCIENCE (MAJOR AND MINOR)
QUALIFICATION CODE: 07BOSC
COURSE: BIOMEDICAL PHYSICS
DATE: JANUARY 2024
DURATION: 3 HOURS
LEVEL: 7
COURSE CODE: BPH702S
SESSION: 1
MARKS: 100
SECOND OPPORTUNITY/ SUPPLEMENTARY: EXAMINATION QUESTION PAPER
EXAMINERS: DR VAINO INDONGO
MOD ERATOR: DR ROSWITA HAMUNYELA
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
Periodic Table
This paper consists of 4 pages including this front page and a Periodic Table.
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QUESTION 1
[20]
1.1 Define the following medical physics terms:
(i) Chemotherapy
(2)
(ii) Brachytherapy
(2)
1.2 Differentiate between malignant and benign tumours.
(6)
1.3 The compressive strength of a giraffe bone is 2.4£14 N/m 2 • Estimate the compressive strain
and elastic modulus of 84 cm long bone, when compressed by 2.6 mm.
(6)
1.4 (i) State Wolfs Law.
(2)
(ii) Explain, in short, why is lubrication essential in a mechanical or human machines? (2)
QUESTION 2
[20]
2.1 State and discuss the types of pressures of the heart essential for blood circulation.
(4)
2.2 A nozzle with a radius, rn = 20.00 mm was attached to a garden hose ofradius, rh = 4rn.
The flow rate through hose and nozzle is 120.00 Lis.
Calculate the speed of the water in the hose.
(4)
2.3 Figure 1 illustrates the steady (laminar) flow of incompressible fluid through an enclosed
tube/pipe. Use the information on the diagram and derive the equation of continuity. (5)
Figure. I
2.4 Stipulate and discuss the two main essential circuit of the cardiovascular system.
(4)
2(Page
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2.5 Write down an expression of hydrostatic pressure (dp) with respect to depth or height (dz).
(3)
OUESTION3
[20]
3 .1 Estimate by calculating the pulse-echo period in µs when the depth of fetus from the ultrasound
probe is 1.5 cm.
(4)
= ( 3.2 If the intensity ofreflected ultrasound is R
22 21 2
-)
, show
that
the
intensity
for
Z2+Z1
transmitted ultrasound wave is given by T=
4
ZiZz]Z_
(6)
[Z1+Zz
3.3 The relative sound intensity is measured on a logarithmic scale. Calculate the
relative intensity of a sound beam is;
(i) Reduced by 40%.
(2)
(ii) A two-fold increase.
(2)
3.4 Define a spin state. Which nucleic particle possesses a spin? And what are the two
microscopic properties of this particle responsible for magnetic resonance imaging?
(4)
3.5 Calculate the total nuclear spins on the 2H atom.
(2)
QUESTION 4
[20)
4.1 An x-ray machine commissioned in Roman Catholic Hospital has tungsten (1nw) as a target
material. One male patient with a fracture on the leg had to undergo radiographic procedure
for medical practitioners to determine the severity of a fracture. The radiologist, oncologist
and radiographer had to decide on the voltage of 95, 100 and 120 ke V for settings during the
procedure, respectively. All medical personnels mutually agreed for an average potential
difference to be set on the instrument. Compute the energy of X-rays which passes through
the leg this procedure.
(5)
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4.2 A radiation with a frequency of 3.13EI 5 Hz releases an electron from a copper plate. The
kinetic energy of the electron is l.70E-18J. Calculate the work function of the plate. Planck's
constant h = 6.63E-34 Js.
(5)
4.3 Use the equation oflinear attenuation to derive an equation of the form y = mx + c.
(5)
4.4 The half-value thickness of a 100 keV X-ray photons passing through aluminium is 2.4E-3
m. If the initial intensity of the beam is 4.2ES W. m- 2 , what would be the intensity of the
beam after passing through a 3 value layers?
(3)
4.5 The increase in the X-ray tube current is proportional to the rate of thermionic emission from
the cathode. List any two effects on the that can be observed with increase in tube current.(2)
QUESTIONS
[20)
5.1 A radionuclide with a physical half life and a biological half-life o/8.0 and 5.6 hours,
respectively, was administered to a patient in Nuclear Medicine Department for imaging.
= = (i) Use the relationship Aeff Ab + Ap to show that Teff
Tp.TTb.
(3)
Tp+ b
(ii) Estimate the effective half-life (in hours) of the radionuclide.
(3)
5.2 Estimate the time elapsed (in seconds) for a radionuclide's activity of 30 mBq reduces with
= 15% of its initial activity and t!. 2.5 days.
(5)
2
5.3 During pair production a positron and electron with mass energies annihilates to produce
photons with energy 0.61 MeV each. Both positron and electron have a mass of9.I09E-31
kg. Estimate the total radiant energy (MeV) transferred into matter. Note: c = 3.00E8 mis
and 1 MeV = 1.602£-13 J.
(5)
5.4 Elucidate both the radical and target theories in terms biological effects of ionizing radiation.
(4)
END
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