Magnetism Flashcards
Which quantity characterizes the strength of a magnet?
Magnetic moment (m or mu)
What is magnetic moment?
A physical quantity that describes the stength of a magnet.
What is magnetic flux density (B)?
A physical quantity that characterizes the strength a magnetic field - e.g. the density of the field lines.
What physical quantity is used to describe the the strength of the magnetic field?
Magnetic flux density (B).
What happens when a magnetic is placed into an external magnetic field?
What does the interaction depend on?
There is an interaction between the magnet and the magnetic field.
The interaction depends on the magnetic moment of the magnet (m) and magnetic flux density (B) of the field lines.
The energy of the interaction between a magnet and an external magnetic field …
.. is proportional to their product (m*B).
What happens to the energy of the magnet when aligned with field lines of an external magnetic field?
The energy is lower.
We need to exert force and work to increase the energy of the magnet.
A. What is the magnetic effect of electric current?
B. How is the electric current and magnetic flux density related?
A conductor generates a magnetic field around itself IF electric current flows through it.
B. The magnetic flux density (B) is proportional to the electric current.
What induces a magnetic field?
Moving charges.
What is electromagnetic induction?
When a magnetic field changes over time and therefore generates an electric field.
E.g. moving a magnet in and out of a voltmeter.
What is self-induction?
The current change causes a change in the magnetic field.
This happens every time a circuit is switched on or off.
What is a LC circuit/resonant circuit?
A circuit consisting of a coil and a capacitor.
Compare the electric and magnetic interactions - which is correct:
A) Like electric charges attract but like magnetic poles repel.
B) While electric charges may exert attractive or repulsive force, magnets may exert only attractive.
C) electric charges can be isolated from each other but magnetic poles cannot.
D) Magnetic poles can be isolated from each other but electric charges cannot.
C).
What is the SI unit of magnetic flux density?
Tesla.
How can a nearly homogeneous magnetic field be created?
A conductor coil with current flowing through it.
