Medical Laboratory Basic Physics Summer Course

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Questions and Answers

Which area of physics involves the study of electron motion and energy gaps?

Optics

Electricity (correct)

Thermodynamics

Magnetism

In which medical imaging technique is Nuclear Magnetic Resonance utilized?

Electrophoresis

X-Ray Diffraction

Ultrasonography

Magnetic Resonance Imaging (correct)

Which of the following is NOT typically associated with basic physics in medical laboratory devices?

Heat

Electricity

Biochemistry (correct)

Magnetism

What does the study of optics in basic physics include?

Reflectivity and transmission Signup and view all the answers

Which of the following medical devices is primarily associated with magnetic imaging techniques?

MRI Machine Signup and view all the answers

What is the equivalent of 0.3 percent in parts per thousand?

0.3 ppt Signup and view all the answers

Which unit would be appropriate for expressing a concentration of 300 parts per million?

0.3 % or 300 ppm Signup and view all the answers

What is one possible replacement for parts per billion?

ppb can be replaced with pL/L Signup and view all the answers

What is the typical symbol used for part per million?

ppm Signup and view all the answers

Which concentration unit is rarely used?

ppq Signup and view all the answers

What is the formula to calculate the change in length due to thermal expansion?

L = L0 (1 + αΔT) Signup and view all the answers

What does the coefficient β represent in the context of area expansion?

The differential form of area change over temperature Signup and view all the answers

If α is the coefficient of linear thermal expansion, what is the value of γ for volumetric expansion?

3α Signup and view all the answers

How is the area (A) of a material affected by a temperature change?

A = A0 (1 + βΔT) Signup and view all the answers

What is the relationship between α and β?

β = 2α Signup and view all the answers

Which equation correctly expresses the change in volume of a rectangular parallelepiped?

V = V0(1 + 3αΔT) Signup and view all the answers

What is the definition of the coefficient α?

Fractional change in length to change in temperature Signup and view all the answers

In the formula A = A0(1 + 2αΔT), what does A0 represent?

Initial area before temperature change Signup and view all the answers

What is the coefficient of thermal expansion defined as?

The ratio of fractional volume change to temperature change Signup and view all the answers

Which factor can cause negative thermal expansion?

Phase transition Signup and view all the answers

Which type of vibration primarily contributes to negative thermal expansion in certain materials?

Transverse vibration Signup and view all the answers

How is the coefficient of planar expansion expressed mathematically?

γ = dV / (V * dT) Signup and view all the answers

What defines the 'rigid unit modes' in materials exhibiting negative thermal expansion?

Strong M–O bonds preventing distortion Signup and view all the answers

In the context of negative thermal expansion, what does the term 'transverse vibration' refer to?

Vibrations that decrease M–M distances Signup and view all the answers

What happens to the volume of some materials upon heating in negative thermal expansion?

Volume contracts Signup and view all the answers

What characteristic of framework minerals leads to negative thermal expansion at high temperatures?

Strong M–O bonds with weak hinges Signup and view all the answers

What is the primary function of a bi-metal strip in a thermostat?

Regulating electrical current based on temperature changes Signup and view all the answers

What characteristic of the bi-metal strip allows it to function in a thermostat?

One metal expands more than the other when heated Signup and view all the answers

What is a potential benefit of using zero expansion composite materials?

Maintaining optical properties across temperature variations Signup and view all the answers

What triggers thermal stresses in a material?

Constraints preventing free expansion or contraction Signup and view all the answers

Which statement best describes negative thermal expansion materials?

They contract and cause tensile stress on adjacent materials Signup and view all the answers

Which factor does NOT typically contribute to thermal stresses?

Presence of internal voids Signup and view all the answers

What does the bending of the bi-metal strip indicate?

A rise in temperature Signup and view all the answers

What is a common effect of thermal expansion in engineering?

Weakening of structural integrity Signup and view all the answers

What is the behavior of water as it cools from 0 to 4°C?

The volume decreases. Signup and view all the answers

Why do icebergs float on water?

Ice expands upon freezing. Signup and view all the answers

What happens to the water at the surface when air temperature falls below 0°C?

It becomes denser and sinks. Signup and view all the answers

What is the temperature at which water has its minimum volume?

4°C Signup and view all the answers

What structural feature of water contributes to its unusual properties?

Hydrogen bonds. Signup and view all the answers

What is dry ice composed of?

Solid carbon dioxide. Signup and view all the answers

How does a rivet work when it cools after being hammered into place?

It contracts and pulls the plates together. Signup and view all the answers

What is the state of dry ice at –78°C?

It is a solid that sublimes. Signup and view all the answers

Study Notes

Medical Laboratory Program 1st Level Summer Course - Basic Physics

Course Instructor: Prof. Dr. Soltan Soltan
Department: Physics Department, Faculty of Science, Helwan University
Topic: Basic Physics for Medical Laboratory Devices

Introduction

Medical Laboratory Devices and Physics Importance: Physics is crucial to understanding device applications in medical labs.
Basic Physics: Covers various physics principles relevant to medical lab devices.

Topics Covered

Heat: Effects of temperature on structure/phase state.
Electricity: Electron motion, conductivity, resistivity, energy gap.
Magnetism: Spin, moment, Electron spin resonance (ESR).
Optics: Reflectivity, transmission, emission, lenses.
Applications and Devices: X-ray, magnetic imaging, radiation.

Medical Laboratory Devices and Output Images

XRD: X-Ray Diffraction
NMR: Nuclear Magnetic Resonance
MRI: Magnetic Resonance Imaging

Dimensionless Numbers (Table 1)

Various units for parts per hundred (%), million (ppm), billion (ppb), trillion (ppt), quadrillion (ppq), etc. are listed with examples and potential replacements.

Course Content

Chapter I: Heat Phenomena and Thermal Physics
Chapter II: Heat and Matter
Chapter III: Calorimetry
Chapter IV: Thermometry
Chapter V: Heat Transfer
Chapter VI: Thermal Analysis

Heat and Matter

Heat energy effects on a body lead to reversible effects like changes in temperature, state (solid to liquid, liquid to vapour), phase, size/structure, physical properties (electric, magnetic) and color.

Heating and Cooling Curves

Heat energy changes state.
Heat energy increases temperature.
Reverse changes happen on cooling.
Heating/cooling curves show these changes.

Phase Diagrams

Most materials undergo phase transformations.
Phase diagrams show equilibrium phases for given chemical compositions.
Types of phase diagrams include unary, binary, ternary, constitutional diagrams.

One Component Systems

Three areas represent solid, liquid, gas states where only one phase exists.
Three lines show transition between one phase to another or existence of two phases if isolated.
Melting point, sublimation point, boiling point/condensation point are equilibrium conditions.
Triple point shows where solid, liquid, and gas coexist.

Pressure-Temperature Equilibrium Phase Diagrams

Equilibrium phase diagrams are divided into two classes of substances.
First class substances expand upon solidification (e.g.; water, bismuth).
Second class substances contract upon solidification (e.g.; carbon dioxide, oxygen).

Phase Equilibria and Phase Rule

Phase (P): a homogenous physically distinct portion of a system.
Number of Components (C): the smallest number of constituents for expressing composition in chemical formula form.
Degrees of freedom (F): number of variables that can be varied.

Effect of Pressure on Phase Transformations

Vapor pressure relates to the pressure of its vapour in equilibrium with liquid or solid.
Vapor pressure graphs are curves of vapor pressure versus temperature.
Vapor pressure is only a function of temperature not volume,and not dependent on the relative amount of vapor, solid, or liquid. -Boiling point: Temperature at which vapor pressure equals external pressure. -Sublimation temperature: Temperature at which vapor pressure equals external pressure.
- Melting point: Temperature at which vapor pressure equals external pressure.

Change in Size/Fundamentals

Some volume change is associated with phase transformations.
Change in size during heating/cooling can be considered in temperature ranges where no phase change is occurring.
Thermal energy is often in the form of atomic vibrations of varying amplitude.

Vibrational Modes

Atoms vibrate longitudinally or transversely.
Longitudinal vibrations: atoms vibrate along the bond direction.
Transverse vibrations: atoms vibrate perpendicular to the bond direction.

Rigid Unit Modes

Stiff tetrahedra or octahedra (strong M-O bonds, short O-O distances) exhibit certain bending potentials.

Animations showing the potential structural flexibility of ZrW2O8

Visual representations of structural change in ZrW2O8.

Change in Volume of Water

Exceptions to general rule in water volume changes:
Water contracts when melting from solid to liquid, and decreases in volume from 0 to 4°C, then after 4°C it expands.
Water has minimum volume and maximum density at 4°C.

Consequences of Anomalous Behaviour of Water

Ice expands upon freezing → ice floats.
Water at surface becomes cooler, denser, and sinks to bottom.

Structure of H₂O

Hydrogen bonds cause unusual properties in water, including large heat of vaporization and expansion upon freezing.
Ice has an open solid structure and therefore is less dense than liquid water.

Dry Ice

Solid carbon dioxide.
Sublimes at -78°C (solid directly changes to gas).
Rapid expansion of CO2 gas.

Applications of Thermal Expansion

The Rivet: Heating hammered rivet contracts tightly fixing plates.
Positive Thermal Expansion: Explained through Thermostat example (bimetallic strip)

Negative Thermal Expansion

In some materials, thermal expansion can be negative, in other words, the material contracts when heated.
Thermal expansion issues in engineering applications, leading to zero expansion composite materials.

Thermal Stresses

Mechanical stress due to constraint during thermal expansion/contraction.
Not free expansion causing thermal stress in structures because of geometry or external constraints.
Temperature gradients also contribute.

Smart Materials:

Smart Resistors (PTC): Unusual resistivity behavior with temperature for self-protection circuits.
Thermochromic Materials: Change color reversibly with temperature. Explained through example of paint/printing/inks, thermochromic pigments for temperature-changes.

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Description

This quiz covers essential topics in basic physics relevant to medical laboratory devices. Learn about heat, electricity, magnetism, and optics, and their applications in devices such as X-ray, MRI, and NMR. Designed for students in the Medical Laboratory Program at Helwan University.