presentations
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Learning resources
Magnetic Domains
Electromagnetic Deflection in a Cathode Ray Tube, I
Electromagnetic Deflection in a Cathode Ray Tube, II
The Magnetic Field Around a Wire, I
Magnetic Field Lines Around a Wire, II
Magnetic Field of a Solenoid
Electromagnetic Induction
The Motor Effect (Lorentz Force)
Please note that the above links and hand rules below have been adapted from the "National High Magnetic Field Laboratory".
Electromagnetic Deflection in a Cathode Ray Tube, I
Electromagnetic Deflection in a Cathode Ray Tube, II
The Magnetic Field Around a Wire, I
Magnetic Field Lines Around a Wire, II
Magnetic Field of a Solenoid
Electromagnetic Induction
The Motor Effect (Lorentz Force)
Please note that the above links and hand rules below have been adapted from the "National High Magnetic Field Laboratory".
The Left Hand RuleThe Left Hand Rule shows what happens when charged particles (such as electrons in a current) enter a magnetic field. You need to contort your hand in an unnatural position for this rule, illustrated below. As you can see, if your index finger points in the direction of a magnetic field, and your middle finger, at a 90 degree angle to your index, points in the direction of the charged particle (as in an electrical current), then your extended thumb (forming an L with your index) points in the direction of the force exerted upon that particle. This rule is also called Fleming's Left Hand Rule, after English electronics pioneer John Ambrose Fleming, who came up with it. |
The Right Hand RuleThe Right Hand Rule, illustrated above, simply shows how a current-carrying wire generates a magnetic field. If you point your thumb in the direction of the current, as shown, and let your fingers assume a curved position, the magnetic field circling around those wires flows in the direction in which your four fingers point.
*** Note this is only for positive current flow. Since we tend to use the idea of moving electrons (negative current flow) in physics 30, you can use the second left hand rule. This rule is the same as above, but with the left hand (so the magnetic field moves in the opposite direction). |
simulations & Gizmos
The above sims are available courtesy of PhET