Currents in мetals презентация
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- 2. Lecture 11 Currents in Metals The effects of magnetic fields.
- 3. Types of Conductivity Conductors are materials through which charge moves easily.
- 4. Drift speed of electrons There is a zigzag motion of an
- 5. So when we consider electric current as a flow of electrons:
- 6. Current in metals Every atom in the metallic crystal gives up
- 7. Resistivity A conductor with current: Current density: I – electric current
- 8. Conductivity A current density J and an electric field E are
- 9. Ohm’s law again For many materials (including most metals), the ratio
- 10. Magnets A single magnetic pole has never been isolated. Magnetic poles
- 11. Magnet Poles Magnet field lines connect unlike poles. Magnet field lines
- 12. Magnet Force The magnitude FB of the magnetic force exerted on
- 13. The text in the previous slide can be summarized as: So
- 14. Direction of FB Right hand rule: The fingers point in the
- 15. Magnetic field direction Magnetic field lines coming out of the paper
- 16. Magnetic Force on a Current Magnetic force is exerted on a
- 17. n is the number density of charged particles q n is
- 18. Arbitrary shaped wire The force on a small segment of an
- 19. Curved Wire in a Uniform Magnetic field as B is uniform:
- 20. Magnetic force on a straight wire So, the force on a
- 21. Loop Wire in a Uniform Magnetic field The net magnetic force
- 22. Current Loop Torque in a Uniform Magnetic Field - Overhead view
- 23. When the magnetic field is parallel to the plane of the
- 24. When the loop is not parallel to the magnetic field, i.e.
- 25. Area Vector In formula for torque we have vector
- 26. Right – hand rule for loop The direction of the magnetic moment
- 27. Magnetic Moment The vector product IA is defined to be the
- 28. Potential Energy of a Magnetic Moment The potential energy of a
- 29. Motion of a Charged Particle in a Uniform Magnetic Field
- 30. Using the obtained formula we get the angular velocity here
- 31. Lorentz Force In the presence of E and B, the force
- 32. The Hall Effect When a current-carrying conductor is placed in a
- 33. the magnetic force exerted on the carriers
- 34. Using that A=td – cross sectional area of the conductor, Using
- 35. When the charge carriers in a Hall-effect apparatus are negative, the
- 36. Units in Si Magnetic field B T= N*s/(C*m) T= N/(A*m)
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