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Chapter 1 Overview of static electricity( On Electric Force , field and, Electric potential, capacitance and dielectrics). http://www.fayoum.edu.eg/nmh E-Mail: [email protected] 3-10-2016 FCI 1 اجندة العام الجامعى 2016/2017 بدء العام الدراسي االحد الموافق .25/9/2016 امتحان اعمال الفصل الدراسي االول من السبت 12/11/2016الي الخميس .17/11/2016 االمتحانات العمليه والشفويه للفصل الدراسي االول يوم السبت 24/12/2016 الي يوم الخميس 29/12/2016 نهايه الفصل الدراسي االولي يوم الخميس 5/1/2017 امتحانات الفصل الدراسي االول يوم االثنين 9/1/2017الي 26/1/2017 اجازه نصف العام من السبت 28/1/2017الي الخميس 9/2/2017 2 FCI 3-10-2016 Hrs / week Course N o Course Title GEN 110 Marks Exam hours Lect Tut Lab Final Y.Work oral Lab Total English Language (1) )1( لغة إنجليزية 2 - - 40 10 - - 50 2 GEN 113 Computational Linguistics لغويات حسابية 2 - - 40 10 - - 50 2 GEN 114 Humanities انسانيات 2 - - 40 10 - - 50 2 GEN 120 Mathematics (1) )1( رياضيات 4 3 - 115 20 15 - 150 3 GEN 125 Physics (1) )1( فيزياء 4 3 2 90 25 10 25 150 3 4 - 4 105 15 10 20 150 3 Basics of computer science أساسيات علوم الحاسب CSC160 3-10-2016 FCI 3 Physics 1 Gen 125 : Electricity REF: Physics For Scientists And Engineers 6E By Serway And Jewett Ch. 1 : Overview of static electricity( Ch. 3 - Direct current and circuit on Electric field and Gauss’ law, Electric potential, capacitance and dielectrics). Ch. 2 : Resistance and current: 2-1 Electric Current 2-2 Resistance 2-3 A Model for Electrical Conduction 2-4 Electrical Power 3-10-2016 FCI 3 -1 Electromotive Force 3 -2 Resistors in Series and Parallel 3 -3 Kirchhoff’s Rules 3 -4 RC Circuits 3 -5 Electrical Meters Inductance: Self learning 4 Physics 1 Gen 125 : Electricity Ref: Physics For Scientists And Engineers 6E By Serway And Jewett Ch. 4 : AC circuits: 4.1 AC Sources 4.2 Resistors in an AC Circuit 4.3 Inductors in an AC Circuit 4.4 Capacitors in an AC Circuit 4.5 The RLC Series Circuit 3-10-2016 FCI 4.6 Power in an AC Circuit 4.7 Resonance in a Series RLC Circuit 4.8 The Transformer and Power Transmission 4.9 Rectifiers and Filters 5 The aim of the course • The graduates have to develop a clear understanding of the basic concepts of electricity and electronics . •Developing the graduate's skills and creative thought needed to meet new trends in science. • Supplying graduates with basic attacks and strategies for solving problems. 3-10-2016 FCI 6 - Intended Learning Outcomes A- Knowledge and Understanding: B- Intellectual Skills: 1) Concept of electric field, electric flux k electric potential and capacitance. 2) Concept Dc circuits and Ac circuits. 3) Investigate the characteristics of simple series circuits that contain resistors, inductors, and capacitors and that are driven by a sinusoidal voltage. 4) Strategies for solving problems related to the previous topics. 1) 2) C- Professional and Practical Skills: 1) 2) 3) D- General and transferable Skills 1) 2) 3) 3-10-2016 FCI Utilizations of theories, rules and basic sciences to interpret physical events. Collecting information from its relevant sources and use it in discussion. Being able to solve problem sheets related to the material course. Collect and record data and information from libraries and summarize it in suitable forms. The student would be able to apply some experiments related to the course contents. Graduate should be able to access data and information from the Internet related to the course subjects. Graduate should develop self professional, scientific, and personal attitude towards continuous education. Graduate should be able to cooperate in teams 7 Chapter 1 Electric Charge and Electric Fields 3-10-2016 FCI 8 Electric Charge Types: Two types of charges Positive: Lack of electrons Negative: surplus of electrons Unit : Coulomb + + 3-10-2016 FCI C - 9 Coulomb`s Law + + K= 8.89 x109Nm2/C2 r 3-10-2016 FCI 10 Coulomb`s Law (N) Ɛo- Another constant called permittivity of vacuum 3-10-2016 FCI 11 Coulomb`s Law Several Charges y +q 1 F 13 F F 13 +q 2 +q 3 X F 23 F 23 3-10-2016 FCI 12 Electric Field Force acting on a unit positive charge at the point. q +++ (N/C) r 3-10-2016 FCI 13 Electric Field Force acting on a unit positive charge at the point. q +++ (N/C) r 3-10-2016 FCI 14 Lines of Force Point Charge - + positive 3-10-2016 FCI negative 15 Lines of Force Dipole 3-10-2016 FCI 16 Lines of Force Two positive charges 3-10-2016 FCI 17 Lines of Force Charged plane +q 3-10-2016 -q FCI 18 Lines of Force Two charged plates -q 3-10-2016 FCI +q 19 More Coulomb’s Law kq1q 2 F12 2 rˆ12 r12 r̂12 r12 r12 +q1 r̂12 r12 +q2 F12 r12 Coulomb’s constant: permittivity of free space: Charge polarity: 3-10-2016 2 2 N m N m 1 9 k 8.988x109 9.0x10 2 C2 C 4o 2 1 C o 8.85x1012 4k N m2 Same sign Opposite sign Force is right Force is Left Electrostatics --- Charges must be at rest! FCI 20 Superposition of Forces F0 F10 F20 F30 .... r10 +Q1 r20 +Q2 r30 +Q3 F30 F20 +Q0 F10 kq 0 q1 kq 0q 2 kq 0q 3 F0 2 rˆ10 2 rˆ20 2 rˆ30 .... r10 r20 r30 N q1 q3 q2 qi F0 kq0 2 rˆ10 2 rˆ20 2 rˆ30 .... kq 0 2 rˆi0 r20 r30 i 1 ri0 r10 3-10-2016 FCI 21 Zero Resultant Force, Example Where is the resultant force equal to zero? q1 = 15.0 mC q2 = 6.0 mC The magnitudes of the individual forces will be equal Directions will be opposite Will result in a quadratic Choose the root that gives the forces in opposite directions 3-10-2016 FCI 22 Electrical Force with Other Forces, Example The spheres are in equilibrium Since they are separated, they exert a repulsive force on each other Charges are like charges Proceed as usual with equilibrium problems, noting one force is an electrical force 3-10-2016 FCI 23 Electrical Force with Other Forces, Example cont. The free body diagram includes the components of the tension, the electrical force, and the weight Solve for |q| You cannot determine the sign of q, only that they both have same sign 3-10-2016 FCI 24 More Field Lines 3-10-2016 Q dq A dA Surface Charge Density: Volume Charge Density: Q dq V dV FCI 25 Superposition of Fields EP E1P E2P E3P .... r10 +q1 E30 E20 r20 +q2 r30 +q3 P E10 kq 3 kq1 kq 2 E P 2 rˆ10 2 rˆ20 2 rˆ30 .... r10 r20 r30 N q1 q3 q2 qi E P k 2 rˆ10 2 rˆ20 2 rˆ30 .... k 2 rˆi0 r20 r30 i 1 ri0 r10 3-10-2016 FCI 26 Superposition Example Find the electric field due to q1, E1 Find the electric field due to q2, E2 E = E1 + E2 Remember, the fields add as vectors The direction of the individual fields is the direction of the force on a positive test charge 3-10-2016 FCI 27 Electric potential, Potential difference in uniform electric field. Electric potential point charge. 3-10-2016 FCI 28 Electric Potential Energy Electrical potential energy is the energy contained in a configuration of charges. Like all potential energies, when it goes up the configuration is less stable; when it goes down, the configuration is more stable. The unit is the Joule. 3-10-2016 FCI 29 Potential difference and electric potential The potential difference ∆V = VB - VA between two points A and B in an electric field is defined as the change in potential energy of the system when a test charge is moved between the points divided by the test charge qo: 3-10-2016 FCI 30 The electric potential is a measure of potential energy per unit charge, the SI unit of both electric potential and potential difference is joules per coulomb, which is defined as a volt (V) that the SI unit of electric field (N/C) can also be expressed in volts per meter: 3-10-2016 FCI 31 3-10-2016 FCI 32 3-10-2016 FCI 33 3-10-2016 FCI 34 3-10-2016 FCI 35 3-10-2016 FCI 36 Electric Field and Electric Potential E=-V/d Two things about E and V: The electric field points in the direction of decreasing electric potential. The electric field is always perpendicular to the equipotential surface. 3-10-2016 FCI 37 Summary Coulomb’s law states that the electric force exerted by a charge q1 on a second charge q2 is The electric field E at some point in space is defined as the electric force Fe that acts on a small positive test charge placed at that point divided by the magnitude q0 of the test charge: The potential difference ∆V = VB - VA between two points A and B in an electric field is defined as the change in potential energy of the system when a test charge is moved between the points divided by the test charge qo: 3-10-2016 FCI 38 Sample Problem Draw field lines for the charge configuration below. The field is 600 V/m, and the plates are 2 m apart. Label each plate with its proper potential, and draw and label 3 equipotential surfaces between the plates. You may ignore edge effects. - - - - - -- - -- - -- - -- - -- - -- - -- - -- - -- - -- - - ++++++++++++++++++++++++++++++++ 3-10-2016 FCI 39 3-10-2016 FCI 40