Electromagnetisism Flashcards
A magnetic field
The region around a magnet or moving charge in which another body with magnetic properties will feel a force
A solenoid
A long coil of current carrying wire
Magnetic flux
The product of magnetic flux density and the area at right angles to the flux. Measured in Weber’s
Magnetic flux density
A measure of the strength of a magnetic field. Measured in Tesla or webers per metre squared
F = BILsinθ
One Weber
The magnetic flux when a magnetic field of magnetic flux density one Tesla passes at right angles through an area of 1m^2
Flemings left hand rule
Shows the direction of the force on a conductor carrying a current in a magnetic field.
Thumb = force
First finger = field
Second finger = current
A velocity selector
A device using perpendicular magnetic and electric fields to select charged particles travelling at a specific velocity
Emf induction
The process of inducing an emf in a conductor when there is a change in magnetic flux linkage across the conductor
Magnetic flux linkage
The product of the magnetic flux through the coil and the number of the turns on the coil
Flemings right hand rule
Thumb = motion of the wire
First finger = direction of the field
Second finger = current
Faradays law
The magnitude of the induced emf is equal to the rate of change of flux linkage
Lenzs law
The direction of any induced emf or induced current is in a direction that opposed the flux change that it caused
Combination of Lenz and Faradays laws:
ε = -(ΔφN) / Δt
A generator
A device used to generate electricity in which the work done to turn the coil within the magnetic field is transferred to electrical energy
Alternating current
Electrical current that reverses it’s direction with a constant frequency
