tailieunhanh - CHAPTER 10: TIME-VARYING FIELDS AND MAXWELL'S EQUATIONS

Tham khảo tài liệu 'chapter 10: time-varying fields and maxwell's equations', khoa học tự nhiên, vật lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 10 TIME-VARYING FIELDS AND MAXWELL S EQUATIONS The basic relationships of the electrostatic and the steady magnetic field were obtained in the previous nine chapters and we are now ready to discuss timevarying fields. The discussion will be short for vector analysis and vector calculus should now be more familiar tools some of the relationships are unchanged and most of the relationships are changed only slightly. Two new concepts will be introduced the electric field produced by a changing magnetic field and the magnetic field produced by a changing electric field. The first of these concepts resulted from experimental research by Michael Faraday and the second from the theoretical efforts of James Clerk Maxwell. Maxwell actually was inspired by Faraday s experimental work and by the mental picture provided through the lines of force that Faraday introduced in developing his theory of electricity and magnetism. He was 40 years younger than Faraday but they knew each other during the 5 years Maxwell spent in London as a young professor a few years after Faraday had retired. Maxwell s theory was developed subsequent to his holding this university position while he was working alone at his home in Scotland. It occupied him for 5 years between the ages of 35 and 40. The four basic equations of electromagnetic theory presented in this chapter bear his name. 322 I e-Text Main Menu Textbook Table of Contents TIME-VARYING FIELDS AND MAXWELL S EQUATIONS 323 FARADAY S LAW After Oersted1 demonstrated in 1820 that an electric current affected a compass needle Faraday professed his belief that if a current could produce a magnetic field then a magnetic field should be able to produce a current. The concept of the field was not available at that time and Faraday s goal was to show that a current could be produced by magnetism. He worked on this problem intermittently over a period of ten years until he was finally successful in 3 He wound two separate .