Magnetic Fields Flashcards
State Faraday’s law of electromagnetic induction
induced e.m.f. is proportional to the rate of change of magnetic flux
State Lenz’s law
the induced current or e.m.f. is in a direction so as to produce effects which oppose the change producing it
How is a magnetic flux density defined?magnetic flux density
The field strength that would cause a wire carrying a current of 1A perpendicular to the field to experience a force of 1N per m of length. B=F/(IL)
magnetic flux
magnetic flux density x area (perpendicular to field direction)
magnetic flux linkage
magnetic flux x the number of turns
tesla
SI unit for magnetic flux density; equivalent to 1 newton per ampere per metre
Weber
SI unit for magnetic flux
What does the spacing of magnetic field lines show?
Magnetic field strength/flux density.
How do you find the direction of the field lines around a current?
Using the right hand grip rule.
How is a field line or current running into the paper shown?
cross in a circle
How is a field line or current running out of the paper shown?
. in a circle
What is represented by the thumb in Fleming’s Left Hand rule.
(Direction of) force
What is represented by the first finger in Fleming’s Left Hand rule.
(Direction of the) magnetic field
What is represented by the second finger in Fleming’s Left Hand rule.
(Direction of) current
When is the equation r = mv/BQ used?
To find the radius of the path of a particle moving in a uniform magnetic field.
