OFRPY102: Basic Physics (Level 1) PDF

Menoufia University Faculty of Applied Health Science Technology OFRPY102: Basic Physics Dr. Mohamed Tharwat Level_1 Basic Physics Session Policy Physics (2) 2 Dr. Mohamed Tharwat Level_1...

Menoufia University Faculty of Applied Health Science Technology OFRPY102: Basic Physics Dr. Mohamed Tharwat Level_1 Basic Physics Session Policy Physics (2) 2 Dr. Mohamed Tharwat Level_1 Basic Physics Instructor Mohamed Tharwat Mohamed Attia Lecturer in Engineering Physics Faculty of Electronic Engineering Google Scholar https://scholar.google.com/citations?user=AEfs6QcAAAAJ&hl=ar ORCID https://orcid.org/0000-0002-0727-2119 Office Hours: After the classes or by appointment Class Schedule: Thursday 9:00 Am – 5:00 PM E-Mail: [email protected] Dr. Mohamed Tharwat Level_1 Basic Physics Course Specifications Maximum Marks Weekly Hours Code Subject Exercise Total Written Oral Work Total Lecture Practical Tutorial OFRPY102 Basic Physics 100 80 -- 20 2 - 2 1 Dr. Mohamed Tharwat Level_1 Basic Physics Course References 1. Raymond A. Serway, Robert J. Beichner Physics for Scientists and Engineers With Modern Physics 2. David_Halliday,_Robert_Resnick,_Jearl_Walker, Fundamentals of Physics 9th Edition. Dr. Mohamed Tharwat ‫‪Level_1‬‬ ‫‪Basic Physics‬‬ ‫"كن شغوفًا بالمعرفة‪ ،‬وستجد العلم متعة ﻻ تضاهى‪".‬‬ ‫‪Dr. Mohamed Tharwat‬‬ Level_1 Basic Physics CH 1 Units and Dimensions Contents CH 2 TEMPERATURE CH 3 HEAT AND WORK CH 4 GASES Dr. Mohamed Tharwat Level_1 Basic Physics CH 5 ELECTRICITY Contents CH 6 MAGNETISM CH 7 REFLECTION AND REFRACTION OF LIGHT CH 8 ATOMIC PHYSICS, NUCLEAR PHYSICS AND NUCLEAR RADIATION Dr. Mohamed Tharwat  Menoufia University Faculty of Applied Health Science Technology OFRPY102: Basic Physics CH 1 UNITS AND DIMENSIONS Course Lecturer DR. Mohamed Tharwat Lecturer in Engineering Physics Faculty of Electronic Engineering 9 Level_1 Basic Physics OUTLINE 1. INTRODUCTION 2. PHYSICS AND MATHEMATICS 3. UNITS 4. DEFINITIONS OF BASE UNITS 5. DIMENSION 6. DIMENSIONAL ANALYSIS 7. SOLVED PROBLEMS 10 Dr. Mohamed Tharwat Level_1 Basic Physics 1. INTRODUCTION 1. INTRODUCTION WHAT IS PHYSICS ? The nature around us is colourful and diverse. It contains phenomena of large varieties. The winds, the sands, the waters, the planets, the rainbow, heating of objects on rubbing, the function of a human body, the energy coming from the sun and the nucleus there are a large number of objects and events taking place around us. 11 Dr. Mohamed Tharwat Level_1 Basic Physics 1. INTRODUCTION 1. INTRODUCTION WHAT IS PHYSICS ? Physics is the study of nature and its laws. We expect that all these different events in nature take place according to some basic laws and revealing these laws of nature from the observed events is physics.  For example, the orbiting of the moon around the earth, falling of an apple from a tree and tides in a sea on a full moon night can all be explained if we know the Newton's law of gravitation and Newton's laws of motion. Physics is concerned with the basic rules which are applicable to all domains of life. Understanding of physics, therefore, leads to applications in many fields including bio and medical sciences. 12 Dr. Mohamed Tharwat Level_1 Basic Physics 1. INTRODUCTION 1. INTRODUCTION WHAT IS PHYSICS ?  The great physicist Dr R. P. Feynman has given a wonderful description of what is "understanding the nature". Suppose we do not know the rules of chess but are allowed to watch the moves of the players. If we watch the game for a long time, we may make out some of the rules. With the knowledge of these rules we may try to understand why a player played a particular move. However, this may be a very difficult task. Even if we know all the rules of chess, it is not so simple to understand all the complications of a game in a given situation and predict the correct move. Knowing the basic rules is, however, the minimum requirement if any progress is to be made. 13 Dr. Mohamed Tharwat Level_1 Basic Physics 1. INTRODUCTION 1. INTRODUCTION WHAT IS PHYSICS ?  Physics goes the same way. The nature around us is like a big chess game played by Nature. The events in the nature are like the moves of the great game. We are allowed to watch the events of nature and guess at the basic rules according to which the events take place. We may come across new events which do not follow the rules guessed earlier and we may have to declare the old rules inapplicable or wrong and discover new rules. 14 Dr. Mohamed Tharwat Level_1 Basic Physics 1. INTRODUCTION 1. INTRODUCTION WHAT IS PHYSICS ?  Since physics of study the is nature is it ,real the given been has one No. are that rules the discover only We.physics of rules the frame to authority physicists great are Feynman or Einstein ,Newton ,Aryabhat.nature in operating frame and guess could they ,time that at available observations the from because But.way convincing a in observations these explained which physics of laws the great the by discovered rules the if and day any phenomenon new a be can there change to hesitate will one no ,phenomenon this explain to able not are scientists.rules these 15 Dr. Mohamed Tharwat Level_1 Basic Physics 2. PHYSICS AND MATHEMATICS  The description of nature becomes easy if we have the freedom to use mathematics. To say that the gravitational force between two masses is proportional to the product of the masses and is inversely proportional to the square of the distance apart, is more difficult than to write 𝟏 𝟐 𝟐 Further, the techniques of mathematics such as algebra, trigonometry and calculus can be used to make predictions from the basic equations. Thus, if we know the basic rule (1) about the force between two particles, we can use the technique of integral calculus to find what will be the force exerted by a uniform rod on a particle placed on its perpendicular bisector. 16 Dr. Mohamed Tharwat Level_1 Basic Physics 2. PHYSICS AND MATHEMATICS  Thus, mathematics is the language of physics. Without knowledge of mathematics, it would be much more difficult to discover, understand and explain the laws of nature. The importance of mathematics in today's world cannot be disputed. However, mathematics itself is not physics. We use a language to express our ideas. But the idea that we want to express has the main attention. If we are poor at grammar and vocabulary, it would be difficult for us to communicate our feelings but while doing so our basic interest is in the feeling that we want to express. 17 Dr. Mohamed Tharwat Level_1 Basic Physics 3. UNITS Physics describes the laws of nature. This description is quantitative and involves measurement and comparison of physical quantities. To measure a physical quantity, we need some standard unit of that quantity. 18 Dr. Mohamed Tharwat Level_1 Basic Physics 3. UNITS Who Decides the Units ?  How is a standard unit chosen for a physical quantity ? The first thing is that it should have international acceptance. Otherwise, everyone will choose his or her own unit for the quantity and it will be difficult to communicate freely among the persons distributed over the world. A body named Conference Generale des Poids et Mesures (CGPM) also known as General Conference on Weight and Measures in English has been given the authority to decide the units by international agreement. It holds its meetings and any changes in standard units are communicated through the publications of the Conference. 19 Dr. Mohamed Tharwat Level_1 Basic Physics 3. UNITS Fundamental and Derived Quantities Fundamental quantities are those physical quantities that cannot be expressed in terms other quantities. It is an independent quantities. For example: Length, mass, time, temperature, electric current, amount of substance. Derived quantities are those physical quantities that are derived from the combination of fundamental quantities. It is a dependent quantity. For example : force, density, volume, momentum etc. 20 Dr. Mohamed Tharwat Level_1 Basic Physics 3. UNITS Fundamental and Derived Quantities It turns out that the number of fundamental (Base) quantities is only seven. All the rest may be derived from these quantities by multiplication and division. Many different choices can be made for the fundamental quantities. Several systems are in use over the world and in each system the fundamental quantities are selected in a particular way. The units defined for the fundamental quantities are called fundamental units and those obtained for the derived quantities are called the derived units. 21 Dr. Mohamed Tharwat Level_1 Basic Physics 3. UNITS SI Units  In 1971 CGPM held its meeting and decided a system of units which is known as the International System of Units. It is abbreviated as SI from the French name Le Systeme International d'Unites. This system is widely used throughout the world.  Table (1) gives the fundamental quantities and their units in SI. 22 Dr. Mohamed Tharwat Level_1 Basic Physics 3. UNITS SI Units Table 1: Fundamental or Base Quantities Physical Name of Symbol Dimension Besides the seven fundamental Quantity the Unit units two supplementary units Mass Kilogram kg M are defined. They are for plane Length meter m L angle and solid angle. The Time Second s T unit for plane angle is radian with the symbol rad and the Electric current ampere A I unit for the solid angle is Temperature kelvin K K steradian with the symbol sr. Luminous intensity candela cd C Amount of substance mole mol 23 Dr. Mohamed Tharwat Level_1 Basic Physics Factor Prefix Symbol 1018 Exa E 3. UNITS 1015 Peta P 1012 Tera T 109 Giga G SI Prefixes 106 Mega M 103 Kilo K 102 Hecto h Table 2 : SI prefixes 101 Deka da 10-1 Deci d 10-2 Centi c 10-3 Milli m 10-6 Micro µ 10-9 Nano n 10-12 Pico p 10-15 Femto f 24 10-18 Dr. atto a Mohamed Tharwat Level_1 Basic Physics 4. DEFINITIONS OF BASE UNITS  Any standard unit should have the following two properties: (a) Invariability: The standard unit must be invariable. Thus, defining distance between the tip of the middle finger and the elbow as a unit of length is not invariable. (b) Availability: The standard unit should be easily made available for comparing with other quantities. 25 Dr. Mohamed Tharwat Level_1 Basic Physics 4. DEFINITIONS OF BASE UNITS Metre 𝟏  It is the unit of length. The distance travelled by light in vacuum in 𝟐𝟗𝟗,𝟕𝟗𝟐,𝟒𝟓𝟖 second is called 1 m. Kilogram  The mass of a cylinder made of platinum-iridium alloy kept at International Bureau of Weights and Measures is defined as 1 kg. 26 Dr. Mohamed Tharwat Level_1 Basic Physics 4. DEFINITIONS OF BASE UNITS Second Cesium-133 atom emits electromagnetic radiation of several wavelengths. A particular radiation is selected which corresponds to the transition between the two hyperfine levels of the ground state of Cs-133. Each radiation has a time period of repetition of certain characteristics. The time duration in 9,192,631,770 time periods of the selected transition is defined as 1 s. 27 Dr. Mohamed Tharwat Level_1 Basic Physics 4. DEFINITIONS OF BASE UNITS Ampere  Suppose two long straight wires with negligible cross-section are placed parallel to each other in vacuum at a separation of 1 m and electric currents are established in the two in same direction. The wires attract each other. If equal currents are maintained in the two wires so that the force between them is 2x10-7 newton per metre of the wires, the current in any of the wires is called 1 A. Here, newton is the SI unit of force. 28 Dr. Mohamed Tharwat Level_1 Basic Physics 4. DEFINITIONS OF BASE UNITS Kelvin 𝟏  The fraction of the thermodynamic temperature of triple point of water 𝟐𝟕𝟑.𝟏𝟔 is called 1 K. Mole  The amount of a substance that contains as many elementary entities (molecules or atoms if the substance is monatomic) as there are number of atoms in 0.012 kg of carbon-12 is called a mole. This number (number of atoms in 0.012 kg of carbon-12) is called Avogadro constant and its best value available is 6.022045x1023 with an uncertainty of about 0.000031x1023. 29 Dr. Mohamed Tharwat Level_1 Basic Physics 4. DEFINITIONS OF BASE UNITS Candela The SI unit of luminous intensity is 1 cd which is the luminous intensity of a 𝟏 blackbody of surface area m2 placed at the temperature of freezing, 𝟔𝟎𝟎𝟎𝟎𝟎 platinum and at a pressure of 101,325 N/m2, in the direction perpendicular to its surface. 30 Dr. Mohamed Tharwat Credited Hours Programs Level_0 Questions and Discussion 31 Physics (2) Dr. Mohamed Tharwat Credited Hours Programs Level_0 The End Good Luck See You in Next Lecture ISA With my Best Wishes Dr. Mohamed Tharwat 32 Physics (2) Dr. Mohamed Tharwat Level_1 Basic Physics 5. DIMENSION In physics the word dimension denotes the physical nature of a quantity. The distance between two points, for example, can be measured in feet, meters, or inches, which are different ways of expressing the dimension of length. To make it clear, consider the physical quantity force. As we shall learn later, force is equal to mass times acceleration. Acceleration is change in velocity divided by time interval. Velocity is length divided by time interval. Thus, 33 Dr. Mohamed Tharwat Level_1 Basic Physics 5. DIMENSION The symbols used in this section to specify the dimensions of length, mass, and time are L, M, and T, respectively. Brackets [ ] will often be used to denote the dimensions of a physical quantity. It is customary to express the fundamental quantities by a capital letter, e.g., mass (M), length (L),time (T), electric current (I), temperature (K) and luminous intensity (C). We write appropriate powers of these capital letters within square brackets to get the dimensional formula of any given physical quantity. In this notation, for example, the dimensions of velocity v are written , and the dimensions of area A are. The dimensions of area, volume, velocity, and acceleration are listed in Table 3. 34 Dr. Mohamed Tharwat Level_1 Basic Physics Table 3: Dimensional Formulae of Some Physical Quantities: Physical quantity Dimensional Formula Temperature k Heat energy M L2 T 2 Area L2 Entropy M L2 T 2 K 1 Specific heat capacity L2 T 2 K 1 Volume L 3 3 Specific latent heat L2 T 2 Density M L Thermal conductivity M L T 3 K 1 1 Velocity LT Electric charge Q or IT 2 Acceleration LT Capacitance M 1 L2 T 2 Q 2 Momentum M L T 1 Electric current I or Q T 1 Force M L T 2 Electric potential M L2 T 2 Q 1 or M L2 T 3 I 1 Energy, work M L2 T 2 Electric field M L T 2 Q 1 or M L T 3 I 1 Inductance M L2 Q 2 or M L2 T 2 I 2 Power M L2 T 3 1 Resistance M L2 T 1 Q 2 or M L2 T 3 I 2 Frequency T Magnetic flux M L2 T 1 Q 1 or M L2 T 2 I 1 1 2 Pressure M L T Magnetic field vector H L1 T 1 Q or L1 I Torque, couple M L2 T 2 Magnetic field intensity, B M T 1 Q 1 or M T 2 I 1 35 Moment of inertia M L2 Dr. Mohamed Tharwat Level_1 Basic Physics 5. DIMENSION Permeability M L Q 2 or M L T 2 I 2 Permittivity M 1 L3 T 2 Q 2 or M 1 L3 T 4 I 2 36 Dr. Mohamed Tharwat Level_1 Basic Physics 6. DIMENSIONAL ANALYSIS  In physics it’s often necessary either to derive a mathematical expression or equation or to check its correctness. A useful procedure for doing this is called dimensional analysis, which makes use of the fact that dimensions can be treated as algebraic quantities. Such quantities can be added or subtracted only if they have the same dimensions. It follows that the terms on the opposite sides of an equation must have the same dimensions. If they don’t, the equation is wrong. If they do, the equation is probably correct, except for a possible constant factor. 37 Dr. Mohamed Tharwat Level_1 Basic Physics 6. DIMENSIONAL ANALYSIS Limitations of Dimensional Analysis: 1. The method of dimensional analysis dos not give any information about pure numbers (Like ½ , π , etc.) and non-dimensional constants. They have to be determined from experiments. 38 Dr. Mohamed Tharwat Level_1 Basic Physics 6. DIMENSIONAL ANALYSIS Limitations of Dimensional Analysis: 2. This method gives no information about dimensional constants such as the universal constant of gravitation (G) or Planck's constant (h), and where they have to be introduced. 3. This technique is useful only for deducing and verifying 'power relations'. Relationships involving exponential, trignometric functions, etc. cannot be obtained or studied by this technique. e.g. 39 Dr. Mohamed Tharwat Level_1 Basic Physics 6. DIMENSIONAL ANALYSIS Limitations of Dimensional Analysis: 4. In this method, we compare the powers of the fundamental quantities (like M, L, T, etc.) to obtain a number of such equations cannot exceed the number of fundamental quantities, we cannot use this method to obtain the required relation if the quantity of interest depends upon more parameters than the number of fundamental quantities used. i.e. number of equations must be equal to number of unknowns. 40 Dr. Mohamed Tharwat Level_1 Basic Physics 6. DIMENSIONAL ANALYSIS Limitations of Dimensional Analysis: 5. In many problems, it is difficult to guess the parameters on which the quantity of interest may depend. This requires a trained, subtle and intuitive mind. 41 Dr. Mohamed Tharwat Credited Hours Programs Level_0 Questions and Discussion 42 Physics (2) Dr. Mohamed Tharwat Credited Hours Programs Level_0 The End Good Luck See You in Next Lecture ISA With my Best Wishes Dr. Mohamed Tharwat 43 Physics (2) Dr. Mohamed Tharwat