6.3 - Electromagnetism Flashcards
What is a Magnetic Field?
The region around a permanent magnet or a moving charge in which another body with magnetic properties will feel a force
What do Magnetic Field Lines show?
The shape of the field and the direction.
What is a Solenoid?
A long coil of current carrying wire
What is Magnetic Flux?
The product of Magnetic flux density and the area at right angles to the flux. Measured in Webers (Wb). Given by BAcosx, where x is the angle between the field lines and the normal to the surface
What is Magnetic Flux Density?
A measure of the strength of the Magnetic Field, and is defined by the equation for the force on a current carrying conductor: F=BILsinx where
F = Force on the wire
B = Magnetic Flux Density (measured in Teslas, T)
I = Current flowing in the wire
L = Length it wire in the Magnetic Field
x = The angle between the wire and the field lines
What is one Weber?
The Magnetic Flux when a Magnetic Field of Magnetic Flux Density one Tesla passes at right angles through an area of one square metre
What does Flemings Left Hand Rule show?
The direction of the force on a conductor carrying a current in a Magnetic Field.
What is a Velocity Selector?
A device using perpendicular magnetic and electric fields to select charged particles travelling at a specific velocity, which leave the region of crosses fields undeflected
What is Electromagnetic induction?
The process of inducing an e.m.f in a conductor when there is a change in Magnetic Flux linkage across the conductor
What is Induced E.M.F?
The e.m.f produced by electromagnetic induction
What is Magnetic Flux Linkage for a coil?
It equals the product of the Magnetic Flux through the coil and the number of turns on the coil. Measured in Weber Turns.
What is Faradays Law?
The magnitude of the induced e.m.f is equal to the rate of change of flux linkage
What is Lenzs Law?
The direction of any induced e.m.f or induced current is in a direction that opposes the flux change that causes it
What is a Generator?
A device used to generate electricity, in which that work done to turn the coil within the Magnetic Field is transferred to electrical energy. The rotation of a coil within a magnetic field produces a constantly changing flux linkage through the coil. This in turn produces a constantly changing induced e.m.f in the coil.
What is Alternating Current?
Electrical current that reverses it’s direction with a constant frequency
