Transcript Interactions between Electricity and Magnetism
Interactions between Electricity and Magnetism Interactions between electricity and magnetism all involve some motion of either charges (electricity) or changes in the magnetic field. Mag/Elec Interactions Magnetic Force There is a magnetic force whenever a charge (or charged object) moves across a magnetic field. The Force direction obeys the Right hand rule we discussed in class. The equation for this is F = q v B q = amount of charge (C), v = velocity, B = magnetic field (Teslas) Magnetic Force on moving charge Mag/Elec Interactions Right Hand Rule # 1 Point fingers in direction of moving charge q Orient your palm so it’s facing the direction of the magnetic field B Extend your thumb, it’s the direction of the force. This force happens only when the charge moves perpendicular to the magnetic field B. Right hand rule for magnetic force Mag/Elec Interactions A wire carrying a current creates it’s own magnetic field. This field is circular and its orientation is determined by Right hand rule #2 Mag/Elec Interactions Right Hand Rule # 2: to determine the direction of the circular magnetic field around a wire carrying a current. Direct your thumb along the wire in the direction of the current. Your fingers curl in the direction of the circular magnetic field Mag/Elec Interactions Electro-magnets If you coil a wire into a helical form (like wrapping a wire around a cylinder) and run a current through it, each circular coil creates a small mag field. The mag field from each coil “adds up” to create what looks like a magnet with a North and South pole. By running a current through this wire, you “make” a magnet. This is also known as a solenoid.