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BPH702S - BIOMEDICAL PHYSICS - 1ST OPP - NOV 2022 |
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nAmlBIA untVERSITY
OF SCIEnCE Ano TECHn0L0GY
FACULTY OF HEALTH, NATURAL RESOURCES AND APPLIED SCIENCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOROF SCIENCE(MAJOR AND MINOR)
QUALIFICATION CODE: 7BOSC
LEVEL: 7
COURSE CODE: BPH702S
SESSION: NOVEMBER 2022
DURATION: 3 HOURS
COURSE NAME: BIOMEDICAL PHYSICS
PAPER: THEORY
MARKS: 100
EXAMINER(S)
FIRST OPPORTUNITY EXAMINATION QUESTION PAPER
DR. VAINO INDONGO
MODERATOR: DR. NDESHIHAFELAVERA UUSHONA
INSTRUCTIONS
1.
Write all your answers in the answer booklet provided.
2.
Read the whole question before answering.
3.
Begin each question on a new page.
PERMISSIBLE MATERIALS
Non-programmable Scientific Calculator
THIS PAPER CONSISTS OF 4 PAGES
(INCLUDING THIS FRONT PAGE)
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QUESTION 1
[20]
1.1 Explain the following terms: (i) cancer, (ii) oncology, and (iii) radio-resistivity.
(6)
1.2 Differentiate, with at least two points each, between ultrasound and radiographic imaging
modalities.
(6)
1.3 The compressive strength of a bone is 1.8 x 1010 N /m2 .
(i) Estimate the compressive strain of the bone of length of 112 cm that was compressed
by 0.12 cm.
(2)
(ii)Calculate the elasticity of the bone after the compression.
(2)
1.4 Define diffusion and state Graham's law of diffusion.
(4)
QUESTION 2
[20]
2.1 Differentiate between a systole and diastole pressures of the heart.
(4)
2.3 A nozzle with a radius, rn, of 20.00 mm was attached to a garden hose with a radius, rh =
4rn mm. The flow rate through hose and nozzle is 45.00 L/s.
(i) Calculate the speed of the water in the hose.
(4)
(ii) Estimate the cross-sectional area of a hose.
(2)
2.4 Consider a Point Path at a height, h = 1.5 x 10 2 m, above the surface of a liquid of density
= p 1.7 x 104 g/m 3 . Assume the fluid is incompressible and frictionless. Hint: 1 atm =1.01x
10 5 Pa.
(i)
State Bernoulli's equation in mathematical form and define all the terms in the
equations.
(5)
(ii) Show the mathematical expression for the hydrostatic pressure Path.
(2)
(iii) Calculate the gravitational pressure of the liquid at h.
(3)
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QUESTION 3
[20]
3.1 Given that the ultrasound frequency of 2 MHz and wavelengths of 6.5 nm was used
to take an image of a bone. Calculate the acoustic impedance of a bone if the density
of a bone is 2.2 x 103 kg/m 3.
(4)
(Zz-Z,i) = 3.2 If the intensity reflected coefficient of ultrasound is
2
show that the intensity
Zz+Z1
transmitted
coefficient
of ultrasound
wave
is given
by T=
4
ZiZz
[Z1+Zz]
2
•
(6)
3.3 The relative sound intensity is measured on a logarithmic scale. Calculate the relative
intensity of a sound beam is;
(i) reduced by half.
(5)
(ii) a two-fold increase.
(5)
QUESTION 4
[20]
4.1 State two types of x-ray photons and discuss how they are produced in the x-ray tube.
(6)
4.2 A radiation with a frequency of 4.13 x 1015 Hz releases an electron from a copper plate.
The kinetic energy of the electron is 2.00 x 10 - 13 J. Calculate the work function of the
plate. Planck's constant h = 6.63 x 10- 34 Js.
(4)
4.3 Magnetic resonance imaging (MRI) is based on the absorption and emission of energy in
the radio frequency range of the electromagnetic spectrum.
(i) How do we call a picture element that form a magnetic resonance image?
(1)
(ii) What is the abbreviation for slice thickness in MRI?
(1)
4.4 The signal in nuclear magnetic resonance (NMR) spectroscopy results from the difference
between the energy absorbed by the spins which make a transition from the lower energy
state to the higher energy state, and the energy emitted by the spins which
simultaneously make a transition from the higher energy state to the lower energy state.
Mention two factors that influence the MRI signal.
(2)
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4.5 A sample has a T1of 0.8 seconds. The net magnetization from the sample set equal to zero
and then allowed to recover towards its equilibrium value. After 1.0 seconds, what
fraction of the equilibrium magnetization value will be present?
(3)
4.6 A hydrogen sample is at equilibrium in a 4.7 Tesla magnetic field. A constant B1 field of
3.42 x 10-4 Tesla is applied along the +x-axis for 52 µs. What is the direction of the net
magnetization vector after the B1field is turned off? Note: y = 42.58 MHz/T.
(3)
QUESTION 5
[20]
5.1 A radioactive equilibrium between 99mMo and its daughter is a transient equilibrium. The
activity of 99 mMo at time ta is 20 GBq. The parent radionuclide has a half-life of 67 hours
and that of a daughter is 6.05 hours.
(i) Explain in short the term transient equilibrium.
(2)
(ii) Calculate the activity of the parent after 7 days.
(4)
(iii) Calculate the activity of the daughter nuclide after 7 days
(4)
5.2 (i) Prove that the time (t) elapsed during transient equilibrium between parent and
Ad(,1.d-.-1.p))
= - / daughter radionuclides can be expressed as t
In ( A ,1.
d•
p
(ii) Estimate the time elapsed when activity of the daughter is 70% of the initial activity of
the parent nuclide.
(10)
END!!!
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