Lec21V - Lecture 21-1 Lecture Next Tuesdays lecture is...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 21 Lecture 21 -1 Next Tuesday’s lecture is cancelled, to compensate for the second evening exam. Unlike exam 1, there will be no review session. All Physics 241 recitations are cancelled for Wednesday, April 6, 2011 – as was stated in the course syllabus. (Reminder/clarification .)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lecture 21 Lecture 21 -2 Maxwell’s Equations (so far) Gauss’s law 0 inside S Q EdA ε = ur ± ± Gauss’ law for magnetism 0 S BdA = u ru r ± ± Faraday’s law B C d Ed l dt Φ =− u rr ± ± Ampere’s law * 0 C Bdl I μ = u ± ± Note: Klingon boxes on the integral symbols denote “closed surface or loop” [Mac vs PC] Flux and current are what penetrate a surface spanning the loop C
Background image of page 2
Lecture 21 Lecture 21 -3 Parallel-Plate Capacitor Revisited 0 S S Bd l I μ = u rr ± ± For surface S 1 , I s = I , but for surface S 2 , I s = 0 ?? Wait, LHS is the same (because C is the same)! You could make this work if a fictitious current I d is added to I s in such a way that I d is zero for S 1 but is equal to I for S 2 . 0 00 E dQ dV A dV IC dt dt d dt dE d A dt dt ε εε == = Φ 0 E d d I dt Φ will work. Q -Q E ur 0 E = B=0 ? Not experimentally! And is called the displacement current
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lecture 21 Lecture 21 -4 Displacement Current James Clerk Maxwell proposed that “A changing electric field induces a magnetic field” , in analogy to Faraday’s law: “A changing magnetic field induces an electric field”. Ampere’s law is revised to become Ampere-Maxwell law 00 0 0 () E d C d Bdl I I I dt μμ μ ε Φ =+ + ur r ± ± is the displacement current . 0 E d d I dt Φ where
Background image of page 4
Lecture 21 Lecture 21 -5 MAXWELL’S EQUATIONS “COMPLETED” The equations are often written in slightly different (and more convenient) forms when dielectric and/or magnetic materials are present. There are also differential forms of these equations.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/23/2011 for the course PHYS 241 taught by Professor Wei during the Spring '08 term at Purdue University-West Lafayette.

Page1 / 24

Lec21V - Lecture 21-1 Lecture Next Tuesdays lecture is...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online