1. Department of Electrical & Electronic Engineering Presentation on: Fundamental Concepts on Electromagnetic Theory. Group: A NameID Md:Sefat Ahmmad17102931 Md:Razib Hossan17102935 Md:Abdullah Rifat Khan17102936 Md:Sadi Khan(Group leader)17102940 AL-AMIN16102904 Date: Sunday, September 23, 2018

2. Field: If at every point of region, there is a corresponding value of some physical function, the region is called field. There are two types of field: (i)Scalar field (ii)Vector field Scalar field: If the value of physical function at every point is scalar quantity then the field is scalar field. For example: temperature, density etc. Vector field: If the value of physical function at every point is vector quantity then the field is vector field. For vector field a number and a direction are required. For example: velocity, gravitational force etc.

5. Md:Razib Hossen ID:17102935

6. What is Divergence? In vector calculus,divergence is a operator that produces a scalar field,given the quantity of vector field’s source at each point. More technically the divergence represents the volume density of the outward flux of vector field.

7. What is curl? In vector calculus,the curl is a vector operator that describes the infinitesimal rotation of a vector field in three dimension Euclidean space. A vector field whose curl is zero is called irrational curl.

8. What is co-ordinate system? A co-ordinate system is a system designed to establish position with respect to given reference points.The co-ordinate system consists of one or more reference points.

9. There are three kinds of co-ordinate system. That’s are : Cartesian co-ordinate system(x, y,z):That’s system species each point in a plane by the pair of numerical co-ordinate. Cylindrical co-ordinate system(r, θ,z):That’s a three dimension co- ordinates,where each point is specified by the two polar co- ordinate of its perpendicular projection onto same fixed point. Spherical co-ordinate system(r,, Ф,):It is a co-ordinate system for three dimensional space where position of the point is specified by three numbers.

11. Md. Abdullah Rifat Khan ID: 17102936

12. Static Field Static Electric Field Static Magnetic Field

13. Static Electric Field

14. Coulomb’s Law

15. Electric Field Intensity

16. Electric Potential

18. Static Magnetic Field

19. Faraday’s Law of Induction

20. Biot-Savart’s Law

22. Lenz’s Law Lenz’s law states that when an emf is generated by a change in magnetic flux according to Faraday’s Law, the polarity of the induced emf is such, that it produces an current that’s magnetic field opposes the change which produces it. Case-1 Case-2

23. Lorentz Force

24. Md : Sadi Khan ID : 17102940

25.  Current continuity equation  Displacement current

26.  Current continuity equation:  A continuity equation is the mathematical way to express this kind of statement.  For example: The continuity equation for electric charge states that the amount of electric charge in any volume of space can only change by the amount of electric current flowing into or out of that volume through its boundaries

29.  Displacement current:

30.  Equation for displacement current: The equation governing static electric field due to charge at rest and static magnetic field due to steady currents are already derived and are due to Gauss, Ampere & Faraday. They are reproduced here. From Gauss’s Law, From Faraday’s Law,

35. 1.Definition of Maxwell’s equations:Gauss LawGauss’ Magnetism LawFaraday’s LawAmpere’s LawMaxwell’s equations in-  differential form  integral form  free space  Harmonically Varying fields

36. Maxwell’s equations Maxwell's equations describe how electric charges and electric currents create electric and magnetic fields. Further, they describe how an electric field can generate a magnetic field, and vice versa.electric chargeselectric currents

37. Gauss Law Gauss law describes the nature of electric field around electric charges. The law is expressed in terms of electric charge density. The inverted triangle is called as the divergence operator.

38. Gauss’ Magnetism Law You can see that both the equations indicate the divergence of the field. The top equation states that the divergence of the Electric flux density D equals the volume of electric charge density. The second equation states the divergence of the Magnetic Flux Density (B) is null.

39. Faraday’s Law Faraday was a scientist whose experiment setup led to Faraday’s Law which is shown in the figure below. The experiment is not very complex. When a battery is disconnected, no electricity flows through the wire. Hence, no magnetic flux is induced in the iron (Magnetic Core). The iron acts like a magnetic field that flows easily in a magnetic material. The purpose of the core is to form a path for the flow of magnetic flux.

40. Differential form

41. Electric displacement density in C/m2 Magnetic flux density in weber per miter square Magnetic field intensity in ampere per miter square Conduction current density in ampere per miter square. Free charge density in ampere per miter square. Partial derivative w.r.t Here, Harmonically Varying Field:

42. Where Q is the total charge within the volume v. Or, simply Integral form:

43. or and or

44. Thus,summarizing,we have

45. In Free space: Differential Form:

46. Integral form:

47. Harmonically Varying Field: Electric displacement density in C/m2 Magnetic flux density in weber per miter square Magnetic field intensity in ampere per miter square Conduction current density in ampere per miter square. Free charge density in ampere per miter square. Partial derivative w.r.t We know that,

48. Also, Or, We know, Or Here, H=Magnetic field intensity in ampere per miter square As, Electric current=Conduction current+ Displacement current Miu=the permeability of the mediumpermeability