Biophysics for Physical Therapy 2025 PDF

Biophysics for Physical Therapy Prof. Dr. Essam Fadl Abo Zeid Vice Dean of Faculty of Science for Community Service and Environmental Development Physics Department - Faculty of Science Assiut University 3rd floor, Room...

Biophysics for Physical Therapy Prof. Dr. Essam Fadl Abo Zeid Vice Dean of Faculty of Science for Community Service and Environmental Development Physics Department - Faculty of Science Assiut University 3rd floor, Room no. 308 Prof. Dr. E. F. Abo Zeid 10/2/2024 1  Sources & References  R.A. Serway; J.W. Jewett, “Physics for Scientists and Engineers with Modern Physics”, 8th edition, 2011. Russell K. Hobbie; Bradley J. Roth, “Intermediate Physics for Medicine and Biology”, 5th edition, 2015.  David Hallidaay; Robert Resnick. “Fundamentals of Physics”, 9 th edition, 2011. Brewster, Hilary D. , “Heat and Thermodynamics”, Oxford Book, 2009. Prof. Dr. E. F. Abo Zeid 10/2/2024 2  Course Information Course Name: Biophysics Course Course Code: (PHYS 101) Hours: 3 Credits (2h lectures+2h practical) weekly (Total 4 hours weekly) Course Instructor: Prof. Dr. Essam Fadl Abo Zeid Professor of Physics of Materials Science at Physics Department, Faculty of Science, Assiut University. Prof. Dr. E. F. Abo Zeid 10/2/2024 3  Grading The Course is graded as the following: 26.6 % Midterm Exam and Assignments. (40 Marks) 26.6 % Practical Exam and Assignments. (40 Marks) 6.6 % Semester works (10 Marks) 40 % Final Paper Exam. (60 Marks) Total: (150 Marks) Prof. Dr. E. F. Abo Zeid 10/2/2024 4 Midterm Exam and Assignments Midterm Exam: November 2024.(7th week details will be informed) Assignments and Homework: Quiz every two weeks. The quiz will be through the lectures or online a website. Each quiz will be available for one week only. Prof. Dr. E. F. Abo Zeid 10/2/2024 5  Practical Contents 10 Experiments will be demonstrated during this course. 1. Ohm’s Law. 2. Metric Bridge. 3. Magnetic Momentum of short bar Magnet. 4. Mirrors Optics. 5. Mechanical Equivalent of Heat. 6. Lenses Optics. 7. Stokes’ Experiment. 8. Hook’s Law. 9. The Simple Pendulum. 10. Velocity of Sounds Final Practical exam will be on one of the above experiments. Prof. Dr. E. F. Abo Zeid 10/2/2024 6  What Is Biophysics? Biophysics is a branch of science that uses the methods of physics to study biological processes. Physics uses mathematical laws to explain the natural world, and it can be applied to biological organisms and systems to gain insight into their workings. Biophysics helped to understand the structure and function of DNA. Prof. Dr. E. F. Abo Zeid 10/2/2024 7  Course Statement The general objectives of this course are to: Provide a firm understanding of the fundamental biophysics. Enable the applications of basic concepts of physics in the medical and biosciences. Understand how basic physics is related to biomedical applications. Prof. Dr. E. F. Abo Zeid 10/2/2024 8  Content of the Course Chapter 1: Units, Statics Equilibrium and Torque (2 weeks) Chapter 2: Fluid Statics, and Fluid Dynamics (2 weeks) Chapter 3: Heat and Thermodynamic (2 weeks) Chapter 4: Electromagnetic waves and general properties of light (2 week) Chapter 5: Optics and Physics of the eye (2 weeks) Chapter 6: Electricity (one weeks) Chapter 7: Materials properties (2 weeks) Prof. Dr. E. F. Abo Zeid 10/2/2024 9  Content of the Course Chapter 1: Units, Statics Equilibrium and Torque (2 weeks) Chapter 2: Fluid Statics, and Fluid Dynamics (2 weeks) Chapter 3: Heat and Thermodynamic (2 weeks) Chapter 4: Electromagnetic waves and general properties of light (2 weeks) Chapter 5: Optics and physics of the eye(2 weeks) Chapter 6: Electricity ( one week) Chapter 7: Materials properties (2 weeks) Prof. Dr. E. F. Abo Zeid 10/2/2024 10  Chapter 1 Units, Statics Equilibrium and Torque Prof. Dr. E. F. Abo Zeid 10/2/2024 11 Prof. Dr. E. F. Abo Zeid 10/2/2024 12 Physical Quantities Are classified into two types: Base quantities & Derived quantities Base quantity Derived quantity is like is like the brick – the house that was the basic building build up from a collection block of a house of bricks (basic quantity) Prof. Dr. E. F. Abo Zeid 10/2/2024 14  Examples: 1. During a short interval of time, the speed v in m/s of an automobile is given by v=at2+bt3 where the time t is in seconds. Find the units of a and b. 2. The time (𝝉) required for a complete oscillation of a mass m on a spring of the force constant k is 𝑘 𝜏 = 2𝜋 , find the unit of k in the SI system. 𝑚 Prof. Dr. E. F. Abo Zeid 10/2/2024 15 Prof. Dr. E. F. Abo Zeid 10/2/2024 16  A nanometer (nm) is a unit of length equivalent to one billionth (10-9) of a meter.  For comparison, a single sheet of paper is approximately 100,000 nm thick and a strand of DNA is 2.5 nm across.  By studying and controlling matter at this nanoscale (1- 100 nm), scientists can alter individual atoms and molecules.  These alterations can lead to changes in the physical, chemical, biological, and optical properties of matter.  When compared to their larger counterparts, nanoparticles can exhibit more or less strength, flexibility, reactivity, reflectivity, or conductivity. Prefixes Prefixes simplify the writing of very large or very small quantities Prefix Abbreviation Power nano n 10−9 micro  10−6 milli m 10−3 centi c 10−2 deci d 10−1 kilo k 103 mega M 106 giga G 109  Density and atomic mass Density (𝜌) is defined as a mass (m) per unit volume (V) or 𝝆 = 𝒎 𝑽. One mole of a substance is the amount that consist Avogadro's number (NA=6.02×1023 atoms/mole) of atoms or molecules of this substance. Mass of any atom (ma ) given from 𝑨(𝒈 𝒎𝒐𝒍) 𝒎𝒂 = 𝑵𝑨 (𝒂𝒕𝒐𝒎𝒔 𝒎𝒐𝒍) Prof. Dr. E. F. Abo Zeid 10/2/2024 19  Examples: 1. A solid cube of Al (density 2.7 g/cm3 ) has a volume of 0.2 cm3. If the atomic mass of Al is 27 g/mol, how many Al atoms are contained in the cube? [NA=6.02×1023 atoms/mol]. (Answer: 1.2×1022 atoms). 2. Two spheres are cut from a certain uniform rock. One has radius 4.50 cm. The mass of the second sphere is five times greater. Find the radius of the second sphere.(Answer, 7.69 cm). 3. The standard kilogram is a Platinum-Iridium cylinder 39 mm in height and 39 mm in diameter. What is the density of this material?.(Answer, 21.461x103 Kg/m3). Prof. Dr. E. F. Abo Zeid 10/2/2024 20  Statics Equilibrium and Torque The magnitude of torque (𝜏) equals the applied force (F) times the length of arm (r) that is perpendicular to the applied force: 𝜏 = ‫ ܨݎ = ݎ × ܨ‬sin 𝜃, where θ is the angle between the force and r. Prof. Dr. E. F. Abo Zeid 10/2/2024 28  Point and Extended Objects Point Object Extended Object Forces can act only at one point. Force can act at many points. The motion is transitional. The motion can be either transitional or rotational. There is no torque. It may be affected by torque. Prof. Dr. E. F. Abo Zeid 10/2/2024 29 Prof. Dr. E. F. Abo Zeid 10/2/2024 30  Conditions for Static Equilibrium 1. For static equilibrium, the resultant external force must equal zero: 𝐅 = 𝟎 Linear momentum is constant. object is at rest or that its center of mass moves with constant velocity. The resultant external torque about any axis must equal zero: ∑𝝉=0 Prof. Dr. E. F. Abo Zeid 10/2/2024 31  How to Objects get an Equilibrium Prof. Dr. E. F. Abo Zeid 10/2/2024 32  Center of Mass Center of Mass: the point at which the mass of an object is considered to be concentrated. Prof. Dr. E. F. Abo Zeid 10/2/2024 33  How to Objects get an Equilibrium Prof. Dr. E. F. Abo Zeid 10/2/2024 35  Example Suppose your lab friend has a height (L) of 173 cm and a weight (w) of 715 N. You can determine the position of his center of gravity by having him stretch out on a uniform board supported at one end by a scale, as shown in the Figure. If the board’s weight (wb ) is 49 N and the scale reading (F) is 3.50×102 N, find the distance of your lab friend’s center of gravity from the left end of the board. Prof. Dr. E. F. Abo Zeid 10/2/2024 36 Prof. Dr. E. F. Abo Zeid 10/2/2024 37 Prof. Dr. E. F. Abo Zeid 10/2/2024 38  Equilibrium of Human Body Prof. Dr. E. F. Abo Zeid 10/2/2024 39  Equilibrium and Toppling Force Let us assume a person as shown in Fig. Calculate the force applied to the shoulder to topple a person standing at rigid attention (Comparing the torques about point A). Assuming that the mass of the person is 70 kg (the gravitational acceleration g= 9.8 m/s2 ) Prof. Dr. E. F. Abo Zeid 10/2/2024 40 Prof. Dr. E. F. Abo Zeid 10/2/2024 41 Prof. Dr. E. F. Abo Zeid 10/2/2024 42 Prof. Dr. E. F. Abo Zeid 10/2/2024 43  Skeletal Muscles Consist of thousands of parallel fiber:  High variability of the force exerted by the muscle.  The force exerted by the muscle depends on the number of fibers contracting the muscle.  Tendons join the muscle to the bone.  Two tendons: Biceps  Three tendons: triceps. Prof. Dr. E. F. Abo Zeid 10/2/2024 44  Levers: Molding the Muscle Prof. Dr. E. F. Abo Zeid 10/2/2024 45 Prof. Dr. E. F. Abo Zeid 10/2/2024 46  Levers: Molding the Muscle Prof. Dr. E. F. Abo Zeid 10/2/2024 47  The Elbow Prof. Dr. E. F. Abo Zeid 10/2/2024 48  The Force Exerted by The Biceps Prof. Dr. E. F. Abo Zeid 10/2/2024 49  (b) Prof. Dr. E. F. Abo Zeid 10/2/2024 50 Prof. Dr. E. F. Abo Zeid 10/2/2024 51 Prof. Dr. E. F. Abo Zeid 10/2/2024 52  Thanks for your Attention Prof. Dr. E. F. Abo Zeid 10/2/2024 53  Content of the Course Chapter 1: Units, Statics Equilibrium and Torque (2 weeks) Chapter 2: Fluid Statics, and Fluid Dynamics (2 weeks) Chapter 3: Heat and Thermodynamic (2 weeks) Chapter 4: Electromagnetic waves and general properties of light (2 weeks) Chapter 5: Optics and physics of the eye(2 weeks) Chapter 6: Electricity ( one week) Chapter 7: Materials properties (2 weeks) Prof. Dr. E. F. Abo Zeid 10/2/2024 54  Chapter 2 Fluid Statics, and Fluid Dynamics Prof. Dr. E. F. Abo Zeid 10/2/2024 55  Difference Between Fluids and Solids Difference between solids and fluids: 1- A solid is characterized by structural rigidity and resistance to a force applied to the surface. Solids transmit the force with an unchanged direction. 2- A fluid is a liquid, gas, or other material that continuously deforms under an applied shear stress, or external force. Fluids transmit force in all directions. Prof. Dr. E. F. Abo Zeid 10/2/2024 56  Density and Pressure Density of homogenous object is its mass per unit volume. 𝜌 = 𝑚 𝑉 (density definition) 𝟏 𝙜 𝒄𝒎𝟑 = 𝟏𝟎𝟎𝟎 𝒌𝙜 𝒎𝟑 unit conversion is very important. Pressure is the perpendicular force per unit area. 𝒅𝑭 𝑷 = 𝒅𝑨⊥ 𝑝𝑟𝑒𝑠𝑠𝑢𝑒𝑟 𝑑𝑖𝑓𝑖𝑛𝑖𝑡𝑖𝑜𝑛 𝟏𝐏ascal=1𝑷𝒂 = 𝟏𝑵/𝒎𝟐 𝟏 𝐚𝐭𝐦=1.01 x105 𝑵/𝒎𝟐 Examples: 1. Find the relation between N/m2 and dyne/cm2. 2. A living room has floor dimensions of 3.5 m and 4.2 m and a height of 2.4 m. (a) What does the air (𝜌air=1.21 kg/m3 ) in the room weight when the air pressure is 1.0 atm? (b) What is the magnitude of the atmosphere's downward force on the top of your head, which we take to have an area of 0.040 m2? Prof. Dr. E. F. Abo Zeid 10/2/2024 57  Density and Pressure 1- 1 N/m2= 1Kg.m/ m2.S2 =1000g.100 cm/104cm2S2=10 g.cm/S2 =10 dyne /cm2 (What is the relation between Pascal and Torr?) 2-a. The weight W=(mg)=(rVg)=(1.21Kg/m3).(3.5 m.4.2m.2.4m).(9.8 m/s2)=418.35 N W ≈ 420 N. (110 cans of Pepsi have the same weight) 1.01𝑥105 𝑁/𝑚2 2-b. F=P.A=(1 atm)( 1 𝑎𝑡𝑚 )(0.040 m2)= 4.04x103 N This is the weight of the air column from the top of your head to the top of the atmosphere. Homework: Find the pressure increase in the fluid in a syringe when a nurse applies a force of 42 N to the syringe's circular piston, which has a radius of 1.1 cm (answer: 1.1 × 105 Pa). Prof. Dr. E. F. Abo Zeid 10/2/2024 58  Variation of Pressure with Depth Prof. Dr. E. F. Abo Zeid 10/2/2024 59  Example: Homework: 1. (a) Calculate the hydrostatic difference in blood pressure between the brain and the foot in a person of height 1.83 m. The density of blood is 1.06 X 103 kg/m3.. (b) What was the blood pressure (in torr or mm Hg) at the feet? 2. Estimate the force exerted on your eardrum due to the water when you are swimming at the bottom of a pool that is 5.0 m deep and surface area of the eardrum 1 cm2. (F=5 N). Prof. Dr. E. F. Abo Zeid 10/2/2024 60  Pascal's Principle Prof. Dr. E. F. Abo Zeid 10/2/2024 61  Surface Tension Prof. Dr. E. F. Abo Zeid 10/2/2024 62  Surface Tension Prof. Dr. E. F. Abo Zeid 10/2/2024 63  Contact Angle and Wettability Prof. Dr. E. F. Abo Zeid 10/2/2024 64  Capillary Action net Fst=2πrγcosθ Weight force= πr2𝗀hr Prof. Dr. E. F. Abo Zeid 10/2/2024 65  Capillary Action Prof. Dr. E. F. Abo Zeid 10/2/2024 66  Chapter 2 Fluid Dynamics Flow rate Q is defined as the volume of fluid passing by some location through an area over time. 𝑄 = 𝐕 𝐭 , m3/s or L/s (1 m3 = 103 L) where V is the volume and t is the elapsed time. Example: How many cubic meters of blood does the heart pump in a 75- year lifetime, assuming the average flow rate is 5.00 L/min? 5L 1m3 𝑚𝑖𝑛 V= ( 1min )(75Y)( 3 ) 10 𝐿 5.26𝑥105 𝑌 = 2𝑋105 𝑚3. Notes: in the Ideal fluid flow, the fluid is non-viscous & incompressible; hence fluid flow is steady & irrotational. Prof. Dr. E. F. Abo Zeid 10/2/2024 67  Flow Rate and Fluid Velocity Prof. Dr. E. F. Abo Zeid 10/2/2024 68  Example: A nozzle with a radius of 0.250 cm is attached to a garden hose with a radius of 0.900 cm. The flow rate through the hose and nozzle is 0.500 L/s. Calculate the speed of the water (a) in the hose and (b) in the nozzle. The narrower the tube, the faster the liquid. Prof. Dr. E. F. Abo Zeid 10/2/2024 69  Bernoulli’s Equation The narrower the tube, the faster the liquid. So, the kinetic energy increases as well. While the energy is conserved, The change in the kinetic energy comes from the work done to push the fluid. 1 p+2 𝜌𝑣 2 + 𝜌𝑔𝑕 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 Bernoulli’s Equation is a typical example of the Energy Conservation Principle. Prof. Dr. E. F. Abo Zeid 10/2/2024 70  Another form of Bernoulli’s Equation: 1 1 𝑃1 +2 𝜌𝑣12 + 𝜌𝑔𝑕1 = 𝑃2 + 2 𝜌𝑣22 + 𝜌𝑔𝑕2 Special Case: Static Fluid o 𝑃1 +𝜌𝑔𝑕1 = 𝑃2 +𝜌𝑔𝑕2 o Special Case: Same Elevation 1 1 o 𝑃1 +2 𝜌𝑣12 = 𝑃2 + 2 𝜌𝑣22 at h1=h2 o The higher the fluid velocity, the lower the pressure 10/2/2024 71 Prof. Dr. E. F. Abo Zeid  Venturi meter Venturi meter: It is a device that is based on Bernoulli’s theorem and is used for measuring the rate of flow of liquid through the pipes. 𝐴1 From the continuity eq. 𝑣2 = v 𝐴2 1 And from Bernoulli’s eq. 1 1 𝑃1 + 𝜌𝑣12 2 = 𝑃2 + 𝜌𝑣22 2 we get: 1 𝐴1 2 𝑃2 = 𝑃1 − 𝜌𝑣12 2 𝐴2 −1 Homework: In Venturi Meter, the difference in pressure as P1 -P2 =21.0 kPa, find the fluid flow rate in m3/s given that the radius of the outlet tube is 1.00 cm, the radius of the inlet tube is 2.00 cm, and the fluid is gasoline (ρ=700 kg/m3 ). Prof. Dr. E. F. Abo Zeid 10/2/2024 72  Homework Example: Calculate the change in the blood pressure (in dyne/cm2 ) of the blood flowing through an artery, the radius of which is constricted by a factor of 3. Assume that the average velocity in the un-constricted region is 50 cm/s and the portion of the artery is horizontal. Take the density of blood to be 1.06 g/cm3. (Answer 1.06x105 dyne/cm2) 1 𝐴1 2 𝐴1 where, 𝑃1 − 𝑃2 = 𝜌𝑣12 −1 and =9 where 𝑟1 = 3𝑟2 2 𝐴2 𝐴2 Prof. Dr. E. F. Abo Zeid 10/2/2024 73  Viscosity and Poiseuille’s Law Laminar Flow: Because of friction between layers of the liquid, there is a velocity gradient. Prof. Dr. E. F. Abo Zeid 10/2/2024 74  Viscosity and Poiseuille’s Law The force required for a constant speed 𝑣𝐴 is: 𝐹 = 𝜂 𝐿 The viscosity is given by: 𝐹𝐿 𝑁 𝜂 = , ( 𝑚2 ). 𝑠 𝑜𝑟 𝑃𝑎. 𝑠. 𝑣𝐴 Poise is the CGS unit of viscosity and in SI Unit equal to 0.1 Pa. s (0.1 N. s/m2). The higher the erythrocyte sedimentation rate (ESR) the lower the viscosity of the blood. (ESR) in male 0-20 mm/hr. (ESR) in females 0-30 mm/hr. The ESR (the precipitation rate) is typically higher in females than in males and increased gradually with age. Note: The viscosity changes with temperature. Prof. Dr. E. F. Abo Zeid 10/2/2024 75  Some Definitions Heat Sources: chemical reactions, nuclear reactions, electricity and mechanical friction. Temperature: a measure of how hot or cold an object is compared to another object. Thermal Equilibrium: If two objects are in thermal contact and there is no energy exchange the objects are said to be in thermal equilibrium. Prof. Dr. E. F. Abo Zeid 10/2/2024 79  Temperature Scales Example A person with hypothermia has a body temperature of 91.4 °F. What Is that temperature in °C and K? Prof. Dr. E. F. Abo Zeid 10/2/2024 80 Temperature Scales Example A healthy person has an oral Temperature equal to 98.6°F. what would this reading be on the Kelvin Scale? To answer this question, we need to choose the correct conversion equation. Firstly, we convert Fahrenheit to Celsius and convert the Celsius to Kelvin degrees. 5 5 1. 𝑇 ℃ = 9 𝑇 ℉ − 32 = 9 98.6 − 32 = 37 ℃ 2. 𝑇 K = 𝑇 ℃ + 273.15 = 37 + 273.15 = 310.15 K Prof. Dr. E. F. Abo Zeid 10/2/2024 81  Thermal Energy Heat Capacity: The amount of thermal energy required to raise the temperature of an object one degree. 𝑸 = 𝑪∆𝑻 Specific Heat: The amount of thermal energy required to raise the temperature of one gram of a substance one degree. 𝑸 = 𝒎𝒄∆𝑻 Latent Heat: The amount of thermal energy required to change the phase of one gram of a substance. 𝑸 = ∓𝒎𝑳 Prof. Dr. E. F. Abo Zeid 10/2/2024 82 Example: A 0.050 0-kg ingot of metal is heated to 200.0°C and then dropped into a calorimeter containing 0.400 kg of water initially at 20.0°C. The final equilibrium temperature of the mixed system is 22.4°C. Find the specific heat of the metal. 𝑸𝟏 𝑎𝑏𝑠𝑜𝑟𝑏𝑒𝑑 𝑏𝑦 𝑤𝑎𝑡𝑒𝑟 = −𝑸𝟐(𝑙𝑜𝑠𝑡 𝑓𝑟𝑜𝑚 𝑚𝑒𝑡𝑎𝑙) 𝑚𝑤 𝐶𝑤 𝑇𝑠 − 𝑇𝑤 = −𝑚𝑚 𝐶𝑚 𝑇𝑠 − 𝑇𝑚 (0.400Kg)(4186 J/Kg. ⸰C)(22.4°C- 20.0°C)=-(0.050Kg)(Cm)(22.4°C- 200.0°C) Cm= 452.5 J/Kg. ⸰C Unit Factor of Converted to conversion 1 erg 10-7 Joule 1 eV 1.6x10-19 Joule 1 KWh 3.6x106 Joule Cal 4.186 Joule Prof. Dr. E. F. Abo Zeid 10/2/2024 83  Latent Heat Prof. Dr. E. F. Abo Zeid 10/2/2024 84  The latent heat of fusion(melting) is used when the phase change is from solid to liquid. The latent heat of vaporization is used when the phase change is from liquid to gas. If energy is entering the system: This will result in melting (fusion) or vaporization. The amount of the higher-phase material will increase Δ m and Q are positive. If energy is extracted from the system: This will result in freezing or condensation. The amount of the higher-phase material will decrease Δ m and Q are negative. Engineering Physics I Prof. Dr. E. F. Abo Zeid 10/2/2024 85  Heat Transfer Prof. Dr. E. F. Abo Zeid 10/2/2024 86  Conduction Prof. Dr. E. F. Abo Zeid 10/2/2024 87  Convection Convection: is the transfer of heat by mass motion of a fluid from one region of space to another. Natural Convection or Free Convection: if the flow is caused by differences in density due to thermal expansion, such as hot air rising. Forced Convection: if the fluid is circulated by a blower or pump, the process is called. Prof. Dr. E. F. Abo Zeid 10/2/2024 88  Radiation Radiation: is the transfer of heat by electromagnetic waves such as visible light, infrared, and ultraviolet radiation. Radiation and absorption An ideal absorber is defined as an object that absorbs all of the energy incidents on it ❑ Ꜫ = 1 ◼ This type of object is called a black body. ◼ An ideal absorber is also an ideal radiator of energy. Prof. Dr. E. F. Abo Zeid 10/2/2024 89  Thermal Expansion Linear and volume thermal expansion coefficient. ∆𝑳 = 𝜶𝑳𝒊 ∆𝑻 , ∆𝑽 = 𝟑𝜶𝑽𝒊 ∆𝑻 , Example: A segment of steel railroad track has a length of 30.000 m when the temperature is 0.0°C. what is the length at 40 °C? Prof. Dr. E. F. Abo Zeid 10/2/2024 90 Prof. Dr. E. F. Abo Zeid 10/2/2024 91  Macroscopic description of an ideal gas For such a system, experiments provide the following information: First, when the gas is kept at a constant temperature, its pressure is inversely proportional to its volume (Boyle’s law). Second, when the pressure of the gas is kept constant, its volume is directly proportional to its temperature (the law of Charles and Gay–Lussac). ◼ These observations are summarized by the equation of state for an ideal gas: PV = nRT In this expression, known as the ideal gas law, R is a universal constant that is the same for all gases and T is the absolute temperature in Kelvin. ◼ In SI units, in which pressure is expressed in Pascal (1 Pa = 1 N/m2) and volume in cubic meters, the product PV has units of Newton meters, or joules, and R has the value: R = 8.315 J/mol. K ◼ An ideal gas is one for which PV/nT is constant at all pressures. Prof. Dr. E. F. Abo Zeid 10/2/2024 92 Conceptual Examples: Answer. D Answer. E Answer. C Prof. Dr. E. F. Abo Zeid 10/2/2024 93 I. What is the temperature of freezing water? 1) 0 °F 2) 0 °C 3) 0 K B. II. What is the temperature of boiling water? 1) 100 °F 2) 32 °F 3) 373 K C. III. How many Celsius units are between the boiling and freezing points of water? 1) 100 2) 180 3) 273 4. The normal temperature of a chickadee is 105.8 °F. What is that temperature on the Celsius scale? 5. On a cold winter day, the temperature is –15 °C. What is that temperature in °F? 6. Liquid nitrogen has a boiling point of 195.81°C at atmospheric pressure. Express this temperature (a) in degrees Fahrenheit and (b) in Kelvin. Prof. Dr. E. F. Abo Zeid 10/2/2024 94  Examples: 7. Define the Celsius and Fahrenheit scales. Give the relationships between the degree sizes and the zero points. Give equations for conversion from one scale to another and give the temperature value for the ice and steam points in each system. 8. Define the Kelvin scale and explain the kelvin as a unit of temperature. Give the relationship between the Celsius and Kelvin scales. Give the ice and steam points on the Kelvin scale. 9. Answer. C Prof. Dr. E. F. Abo Zeid 10/2/2024 95  Examples: 10. Answer: E 11. Answer: C 12. Prof. Dr. E. F. Abo Zeid 10/2/2024 Answer: 96 C  Examples: 13. Answer: B 14. Answer: D 15. Prof. Dr. E. F. Abo Zeid 10/2/2024 Answer: 97 E  Examples: 16. Answer: C Prof. Dr. E. F. Abo Zeid 10/2/2024 98 Example3 Prof. Dr. E. F. Abo Zeid 10/2/2024 99  Examples: Ex.4 Ex.5 Prof. Dr. E. F. Abo Zeid 10/2/2024 100  Thanks for your Attention Prof. Dr. E. F. Abo Zeid 10/2/2024 101  Chapter 4 Electromagnetic waves and properties of light Prof. Dr. E. F. Abo Zeid 10/2/2024 102  Content of the Course Chapter 1: Units, Statics Equilibrium and Torque (2 weeks) Chapter 2: Fluid Statics, and Fluid Dynamics (2 weeks) Chapter 3: Heat and Thermodynamic (2 weeks) Chapter 4: Electromagnetic waves and properties of light (2 weeks) Chapter 5: Optics and physics of the eye (2 weeks) Chapter 6: Electricity ( one week) Chapter 7: Materials properties (2 weeks) Prof. Dr. E. F. Abo Zeid 10/2/2024 103  Disturb the surface of water and you create water waves. Disturb the molecules of air in the room and you create a sound wave. Disturbing the electromagnetic fields filling space causes electromagnetic waves (light!). Prof. Dr. E. F. Abo Zeid 10/2/2024 104  What are electromagnetic waves? How electromagnetic waves are formed How electric charges produce electromagnetic waves Properties of electromagnetic waves  Electromagnetic Waves Are made by vibrating electric charges and can travel through space by transferring energy between vibrating electric and magnetic fields. Shaking a magnet causes changing magnetic fields, which cause electric fields, which cause magnetic fields, etc. Any changes to electric or magnetic fields causes electromagnetic waves to propagate away from the disturbance. The magnetic and electric fields create each other again and again. Electromagnetic waves are light. Do not need matter to transfer energy.  An EM wave travels in all directions. The figure only shows a wave traveling in one direction. The electric and magnetic fields vibrate at right angles to the direction the wave travels so it is a transverse wave. Prof. Dr. E. F. Abo Zeid 10/2/2024 107  Properties of EM Waves All matter contains charged particles that are always moving; therefore, all objects emit EM waves. The wavelengths become shorter as the temperature of the material increases. EM waves carry radiant energy. Light is a transverse wave of varying electric and magnetic fields. This pattern of fields moves through space, each location experiencing oscillating fields.  What is the speed of EM waves? All EM waves travel Material Speed 300,000 km/sec in space. (km/s) (speed of light-nature’s limit!) Vacuum 300,000 EM waves usually travel Air