1 / 11

36.1 – magnetic poles

36.1 – magnetic poles. Always have two poles 1 pole seeks north, other seeks south Like poles  repulsive Unlike  attractive All magnets have two poles. 36.2 – magnetic fields. Direction of force when magnet is placed in someone else’s location Usually a compass

adora
Download Presentation

36.1 – magnetic poles

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. 36.1 – magnetic poles • Always have two poles • 1 pole seeks north, other seeks south • Like poles  repulsive • Unlike  attractive • All magnets have two poles

  2. 36.2 – magnetic fields • Direction of force when magnet is placed in someone else’s location • Usually a compass • Extends from pole to pole, N  S • Iron (or other magnets) tend to line up parallel to field • Recall how electric fields were generated

  3. 36.3 – the nature of a magnetic field • Moving electric charges generate a magnetic field • Stationary = only electric fields • Atoms have moving electrons  magnetism • Somehow (?) spinning electrons create magnetism • Materials in which spins “coordinate” can become magnetic – Fe, Ni, Co

  4. 36.4 – Magnetic domains • Clusters of aligned atoms – have same relative magnetic field • Presence of magnetism near Fe “forces” an alignment – creating temporary magnet • Permanent magnet – domains stay in place after field is removed

  5. 36.6 – magnetic forces on moving charged particles • Moving charges experience forces w/I magnetic fields • Greatest when perpendicular, zero when parallel • Direction of force is perpend. to field & velocity of charge • Found by using right hand rule • Particles can be steered by mag. Fields • Old style TV’s & Earth

  6. 36.5 – electric currents & magnetic fields • Since moving charges produce magnetism so do electric currents • Field is not radial • Field forms circles around conductor

  7. If wire forms a loop, the field lines are concentrated in the center of loop • Doubling loops – double field strength • Many loops form an electromagnet • Iron placed inside loop coils intensifies magnetic field • Most powerful electromagnets – superconducting

  8. 36.7 – magnetic forces on current carrying wires • Current (moving charges) also causes a deflection (force) on wires • Again perpendicular to field & direction of current • Parallel wire with field = no deflection • Symmetry: current deflects magnetic compass & magnets deflect current carrying wires

  9. 36.8 – meters to motors Galvanometers • Magnetic needle inside loops of wire indicates current – galvanometer • The more coils – the more sensitive • Can be made into a ammeter or voltmeter

  10. Electric motors • Electric motor = galvanometer made to change current direction with every half rotation • Current flow in opposite directions causes forces in opposite directions

  11. 36.9 – earth’s magnetic field • The earth acts as a giant magnet • Geographic/Magnetic poles do not line up • Difference between = magnetic declination • “current” theory – liquid inside (core) is flowing creating magnetism • Magnetism has “switched” (reversed) many times in the past

More Related