I will be undertaking a literature search and review on magnets and their magnetic fields. I’ll
be investigating three areas of research in which magnets are used in the real world and the
science behind them to produce an investigative project proposal on how to detect a
magnetic field. The aim and objective of this investigation is to test the strength of a
magnetic field by measuring the effects of a magnetic field on a current-carrying conductor.
Introduction
A magnetic field is the distribution of energy and a region of space around a magnet in
which another magnet would experience a force and have no boundary. It originates from
the north pole and terminates at the south pole. Magnetic flux density is when the field
lines are close together and when the field lines run parallel to each other, they form a
magnetic field. The equation for magnetic flux density is the number of field lines per unit
area, the symbol for it is a capital B, the units for it is tesla. Magnetic flux is when the
number of lines passing through the surface area is perpendicular to its surface area.
Change in flux is when there is a change in area of the loop going through the field or if the
direction or magnitude of the magnetic field changes
The magnetic domain is what truly creates a magnetic field. When a wire carries a current,
the wire generates its own magnetic field. The magnetic field will interact with the external
magnetic field and as a result with force exerted on the wire.
In today’s world, magnets have become part of daily life for example in the medical field,
more specifically in the radiography department where MRI (magnetic resonance imaging)
machines are used to construct atomic detailed images of the internal body. Another use of
magnets in the real world is maglev trains which are the world’s first levitating trains located
in japan and the compass which is a device made up of a magnetic needle or other elements
like a compass rose or compass card that pivot in alignment with the earth’s magnetic field
in order to detect geographic direction.
Magnets are objects with a magnetic field, an unseeable display of magnetism. A magnet
can do one of two things, it can either repel or attract each other. The different types of
magnets are temporary, permanent and electromagnets. Each of these magnets produces a
different magnetic field. At the occurrence of a magnetic field, Temporary magnets become
magnetised. An Electromagnet is when a material turns magnetised due to an electrical
current flowing through it but when the electricity halts, the material stops being magnetic.
Permanent magnets are always naturally magnetic and usually produced by substances like
nickel or iron. A solenoid is not the same as an electromagnet however a solenoid is a coil of
wires that is used to make an electromagnet when a current is run through it.
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, The magnetic field is its strongest and utmost concentrated at the north and south pole,
which is an area at each end of a magnet. To identify where the magnetic field is its
strongest would be by performing a practical experiment where the material is put in a
magnetic field then a current is run through the material which would cause the magnetic
field to be produced.
In order to test the strength of a magnetic field, a practical must be carried out where a
material is put in a magnetic field then a current is run through the material. The magnetic
field will produce a sideways change in the electric potential across the material so that it is
measured. The change in potential and the size of the material is then utilised to achieve the
magnitude of the magnetic field.
The three metals that are naturally magnetic are iron, cobalt and nickel whilst other metals
like magnesium and copper are not naturally magnetic. These three magnetic metals are
also known as permanent magnets.
Induced magnets (Lenz’s Law) = Lenz’s Law permits for the prediction of an electromagnetic
field induced by changing magnetic field through a loop or coil of wire. The equation for
Lenz’s Law is the negative sign (-) in faradays law induced e.m.f.=−NΔtΔΦ so, induced
e.m.f N=number of turns in coil\ change in magnetic flux\delta t (change in time).
The difference between induced and permanent magnetism is that a permanent magnet
generates its own magnetic field, contrasting to an induced magnet which becomes
magnetised when placed in a magnetic field. Another difference is that when an induced
magnet is detached from the magnetic field it loses either most or all of its magnetism
whereas a permanent magnet only loses its magnetism under some circumstances such as
heat.
Review of literature:
The first source of information I researched for Maglev trains was
(https://www.energy.gov/articles/how-maglev-works) which was written on June 14th of
2016 which makes it outdated as it was written over three years ago. The author of the
article, Chelsea Whyte, a science writer at Brookhaven National Lab is not a reliable source
because she is only a journalist and not a scientist. On the other hand, the organisation
Brookhaven National Lab is a scientific organisation hence the source of information can be
deemed as a valid and reliable as it comes from an organisation that specialises in science
making it more reliable than an organisation that doesn’t specialise or has any relation to
science.
The second source of information I researched for Magnetic Resonance Imaging (MRI)
Machines was (https://www.nibib.nih.gov/science-education/science-topics/magnetic-
resonance-imaging-mri) which does not provide an author or the date it was published on
therefore it is automatically deemed as invalid and unreliable. Nonetheless, I used another
source of information for MRI machines
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121941/ ) which does provide an author,
Abi Berger, who is a science editor. A science editor is an individual who edits scientific
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