Later, during the Middle Ages, navigational compasses
were made using the magnetic properties lodestone. battery made number cells. Electroplating serves double purpose pro-
tecting base metal from atmospheric erosion and also giving more
expensive and attractive appearance.
An anode and cathode dissimilar metal placed electrolyte can
react chemically and produce emf. Lines magnetic flux always form closed loops. The word lodestone is
derived from old English word meaning ‘the way’, and the word mag-
netism derived from Magnesia, the place where magnetic ore was first
discovered. When load connected across
the anode and cathode, current drawn from this arrangement, which
is called cell. The conductors which make contact with
the liquid are called the anode and cathode. They help us
to visualize and explain the magnetic effects. The symbol used for
magnetic flux the Greek letter (phi) and the unit magnetic
flux the weber (symbol Wb), pronounced ‘veber’, commemorate
the work the German physicist Wilhelm Weber (1804–1891). Copper, brass,
wood, PVC and glass are not attracted magnet and are, therefore,
described non-magnetic.
Magnetism
The Greeks knew early 600 that certain form iron ore, now
known magnetite lodestone, had the property attracting small
pieces iron.
2. Silver and nickel plating has long
been used enhance the appearance cutlery, candlesticks and sporting
trophies. Most the aluminium produced today extracted from its ore by
electrochemical methods.
Electrolysis industrial process used the refining metals and elec-
troplating. Small pieces of
lodestone attached wooden splints floating bowl water always
came rest pointing north–south direction. These materials are said ferromagnetic. has many use-
ful applications providing portable electrical power, but electrochemical
action can also undesirable since the basis electrochemical cor-
rosion which rots our motor cars, industrial containers and bridges.
.Basic Electrical Installation Work
112
CHEMICAL EFFECT
When electric current flows through conducting liquid, the liquid is
separated into its chemical parts. was one the earliest industrial applications electric cur-
rent. Lines magnetic flux have physical existence, but they were
introduced Michael Faraday (1791–1867) way explaining
the magnetic energy existing space material. The liquid itself called the
electrolyte, and the process called electrolysis.
Iron, nickel and cobalt are the only elements which are attracted strongly
by magnet.
Some basic rules magnetism
1
