Year 2- Magnetic Fields Flashcards
what is faraday’s law
the magnitude of the induced emf is directly proportional to the rate of change in magnetic flux linkage
what is lenz’s law
the induced emf acts in such a direction to produce effects that oppose the change causing it
what is the experimental technique that proves lenz’s law
when a bar magnet is inserted into a coil of wire, the pole of the coil facing the magnet becomes the pole of the magnet facing the coil.
This is because of lenz’s law: the direction of the induced field in the coil pushes against the change creating it.
what happens when a bar magnet goes through a coil
an emf is induced within the coil due to a change in magnetic flux
a current is also induced, so the coil has its own magnetic field
what happens to the emf if a direct current is replaced with an alternating current
the emf induced will also be alternating with the same frequency as the supply
when is the negative sign in lenz’s law required
when talking about direction, when talking about the magnitude of the emf a negative sign is not required
what is the magnetic flux density
the number of magnetic flux lines passing through a region of space per unit area
what is a magnetic field
a region of space where a magnetic pole will experience a force
what is a magnetic field created by
-moving electric charge/ electrons (current carrying wire)
or
-permanent magnets
what are permanent magnets
materials that produce a magnetic field
what is a magnetic field sometimes referred to as
B-field
what will not produce a magnetic field
a stationary charge
how can magnetic fields be observed if they are invisible
using magnetic materials such as iron
how can the strength of the magnetic field be described
by the density of the magnetic flux lines
