Magnetic Field of a Coil a solenoid is a coil of wire that acts like a magnet when an electric current passes through it the magnetic field inside the coil is uniform which means it has the same strength and acts in the same direction throughout Right Hand Rule #2 fingers wrap in direction of current thumb points in the direction of the magnetic field 13.4 Prac. #1,2

Factors That Affect the Magnetic Field of a Coil The following factors will affect the magnetic field of a coil: 1.Current – magnetic field strength varies directly with current 2.Number of loops - magnetic field strength varies directly with number of loops 3.Type of core material – m.f.s. depends on the material of the core Read sample problem on pg Prac. #3

Relative Magnetic Permeability This is the factor by which a core material increases the magnetic field strength. Ferromagnetic greatly increases magnetism when placed inside a coil i.e. iron, nickel, cobalt Paramagnetic slightly increases magnetism when placed inside a coil i.e. oxygen, aluminum Diamagnetic slight decrease in magnetism when placed inside a coil i.e. copper, silver, water

Applications of Electromagnetism Read and summarize pgs. 487 – Lifting electromagnets 2.Electromagnetic relay 3.Electric Bell - appletapplet 13.4 Prac. #4-6 UC #1-7