Magnetic effect of electric current
By Tisha Gupta X-F
MAGNETIC EFFECT OF ELECTRIC CURRENT
The term ‘magnetic effect of electric current’
means that an electric current flowing in a wire
produces a magnetic field around it . A Magnet
is an object which attracts pieces of iron,
steel, nickel and cobalt. A bar magnet is a long,
rectangular bar of uniform cross-section which
attracts pieces of iron, steel, nickel and cobalt.
MAGNETIC FIELD
A magnetic field is the magnetic influence of electric
currents and magnetic materials. The magnetic field at any
given point is specified by both a direction and a magnitude (or
strength); as such it is a vector field. The term is used for two
distinct but closely related fields denoted by the
symbols B and H, which are measured in units of tesla and amp
per meter respectively in the SI.B is most commonly defined in
terms of the Lorentz force it exerts on moving electric charges.
MAGNETIC FIELD OF EARTH
Earth's magnetic field, also known as the geomagnetic
field, is the magnetic field that extends from the Earth's
interior to where it meets the solar wind, a stream
of charged particles emanating from the Sun. Its magnitude
at the Earth's surface ranges from 25 to 65 microtesla (0.25
to 0.65 gauss). It is approximately the field of a magnetic
dipole tilted at an angle of 10 degrees with respect
to Earth's rotational axis, as if there were a bar
magnet placed at that angle at the center of the Earth.
Unlike a bar magnet, however, Earth's magnetic field
changes over time because it is generated by
a geodynamic (in Earth's case, the motion of molten iron
alloys in its outer core).
Electromagnetism
Electromagnetism, or the electromagnetic force is
one of the four fundamental interactions in nature, the
other three being the strong interaction, the weak
interaction, and gravitation. This force is described
by electromagnetic fields, and has innumerable physical
instances including the interaction of electrically
charged particles and the interaction of uncharged
magnetic force fields with electrical conductors.
Clock face rule
A current carrying loop works like a disc magnet.
The polarity of this magnet can be easily understood
with the help of clock face rule. If the current is
flowing in anti-clockwise direction, then the face of
the loop shows north pole. On the other hand, if the
current is flowing in clockwise direction, then the
face of the loop shows south pole.
SolenoidA solenoid is a coil wound into a tightly packed helix.
The term was invented by French physicist André-Marie
Ampère to designate a helical coil. In physics, the term
refers specifically to a long, thin loop of wire, often
wrapped around a metallic core, which produces a uniform
magnetic field in a volume of space (where some
experiment might be carried out) when an electric
current is passed through it.
ElectromagnetAn electromagnet is a type of magnet in which the magnetic
field is produced by electric current. The magnetic field
disappears when the current is turned off. Electromagnets are
widely used as components of other electrical devices, such
as motors, generators, relays, loudspeakers, hard disks, MRI
machines, scientific instruments, and magnetic separation
equipment, as well as being employed as industrial lifting
electromagnets for picking up and moving heavy iron objects like
scrap iron.
ELECTRIC MOTOR
An electric motor is an electric machine that
converts electrical energy into mechanical energy.
In normal motoring mode, most electric motors operate through
the interaction between an electric motor's magnetic
field and winding currents to generate force within the motor. In
certain applications, such as in the transportation industry
with traction motors, electric motors can operate in both
motoring and generating or braking modes to also produce
electrical energy from mechanical energy.
Direct current (DC)
Direct current (DC) is the unidirectional flow
of electric charge. Direct current is produced by
sources such as batteries, thermocouples, solar cells,
and commutator-type electric machines of
the dynamo type. Direct current may flow in
a conductor such as a wire, but can also flow
through semiconductors, insulators, or even through
a vacuum as in electron or ion beams.
Alternating current (AC)
Alternating current (AC, also ac), the flow
of electric charge periodically reverses direction.
In direct current (DC, also dc), the flow of electric
charge is only in one direction. The
abbreviations AC and DC are often used to mean
simply alternating and direct, as when they
modify current or voltage.
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