Содержание
- 2. Lecture 13 Faraday’s law of induction Lenz’ law Eddy currents Maxwell’s equations
- 3. When a magnet is moved toward a loop of wire connected to a sensitive ammeter, the
- 4. From these observations, we conclude that the loop detects that the magnet is moving relative to
- 5. Initially, when the switch is open, no current is detected by the ammeter. The same is
- 6. So when the switch was open, and is closed, the changing current in the primary circuit
- 7. An electric current can be induced in a circuit by a changing magnetic field. The induced
- 8. Faraday’s Law of Induction The emf induced in a circuit is directly proportional to the time
- 9. Loop in a uniform magnetic field A conducting loop that encloses an area A in the
- 10. Lenz’s Law Faraday’s law (ε=-dФB/dt) indicates that the induced emf and the change in flux have
- 11. Picture (a): When the magnet is moved toward the stationary conducting loop, a current is induced
- 12. As the conducting bar slides on the two fixed conducting rails, the magnetic flux due to
- 13. Induced emf and Electric Fields A conducting loop of radius r in a uniform magnetic field
- 14. ε=-dФB/dt The work done by the electric field in moving a test charge q once around
- 16. General form of Faraday’s Law of Induction Here is integration along an enclosed path. ФB is
- 17. Eddy Currents Circulating currents called eddy currents are induced in bulk pieces of metal moving through
- 18. Eddy currents appears in a solid conducting plate moving through a magnetic field. As the plate
- 19. As the conducting plate enters the field (position 1), the eddy currents are counterclockwise. As the
- 20. Maxwell’s Equations Maxwell’s equations applied to free space, that is, in the absence of any dielectric
- 21. Equation (1): Here integration goes across an enclosed surface, q is the charge inside it. This
- 22. Equation (2): Here integration goes across an enclosed surface. It can be considered as Gauss’s law
- 23. Equation (3): Here integration goes along an enclosed path, ФB is a magnetic flux through that
- 24. Equation (4): This is Ampère–Maxwell law, or the generalized form of Ampère’s law. It describes the
- 25. Maxwell’s Equations Symmetry Equations (1) and (2) are symmetric, apart from the absence of the term
- 26. Maxwell’s equations predict the existence of electromagnetic waves (traveling patterns of electric and magnetic fields), which
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