1 / 7

Electromagnetic Induction

Electromagnetic Induction. Magnetic Flux. The flux density of a magnetic field is defined by the equation: F = B I l where F is the force on a conducting wire I is the current in the conducting wire l is the length of the conducting wire.

lorene
Download Presentation

Electromagnetic Induction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electromagnetic Induction Magnetic Flux The flux density of a magnetic field is defined by the equation: F = B I l where F is the force on a conducting wire I is the current in the conducting wire l is the length of the conducting wire The magnetic flux density gives us an idea of how strong the field is; it is a measurement of how close together the field lines are. The unit is the Tesla T

  2. Consider a loop of wire in a uniform magnetic field: B Cross- sectional area A The magnetic flux linked by a particular loop is given by: mag. flux density x area of loop F = B A ( If the flux density is stronger, the lines are closer together and so more lines, “flux”, are linked.)

  3. If you have N loops of wire then the total flux linked is N times greater: B Cross- sectional area A The total magnetic flux linked is B A N = N F This makes sense when you think of a solenoid; having more turns makes a stronger magnetic field. The unit of magnetic flux is the Weber Wb 1 Wb m-2 = 1 T

  4. Electromagnetic Induction As the coil is moved, an emf is induced in it. Since the circuit is complete, a current can flow.

  5. Electromagnetic Induction direction of movement Reversing: poles of magnet connections to ammeter reverses direction of current

  6. A straight conductor moving in a magnetic field N S Consider a wire moving in a magnetic field The electrons in the wire are moving perpendicular to the field, so there is a force on them given by FLHR. This force is given by F = B q v Electrons are forced perpendicular to B and v, i.e. along the length of the wire This means an emf is induced in the wire.

  7. N S If you think about FLHR, you can see the force pushing the electrons along the wire gives rise to a conventional current flowing out of the paper. If you then apply FLHR rule again, this produces a force opposite to the original movement. So, emf induced causes a current to flow which opposes change which caused it. This is known as Lenz’s Law

More Related