Magnetism and Electromagnetism Notes (Pages 582-9)

17.1 The Magnetic Force- Another Force at a Distance

• A magnetic field is the distribution of a magnetic force in the region of a magnet. 
• There are two magnetic characteristics, lebelled north and south, that are responsible for magnetic forces. Similar magnetic poles repel one another while dissimilar poles attract one another.
• Magnets attract certain metals such as iron, nickel, and cobalt, which are not magnetic. These are called ferromagnetic metals.
• Domain Theory- All large magnets are made up of many smaller and rotatable magnets, called dipoles, which can interact with other dipoles close by. If dipoles line up, then a small magnetic domain is produced.

17.2 Electromagnets

• Oersted's Principle- Charge moving through a conductor produces a circular field around the conductor.
• Scientists have developed several hand signals to predict how magnetic forces act, known as right hand rules because they involve using your right hand.

• RHR#1: Grasp the conductor with the thumb of the right hand pointing in the direction of conventional, or positive (+), current flow. The curved fingers point in the direction of the magnetic field around the conductor.
  
  
• RHR#2: Grasp the coiled conductor with the right hand such that curved fingers point in the direction of conventional, or positive (+), current flow. The thumb points in the direction of the magnetic field within the coil. Outside the coil, the thumb represents the north (N) end of the electromagnet produced by the coil.