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Проверь себя - ORT Marseille

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Imagine as if you were a
pupil. Let us solve the
game-test. Draw physics.
How does the radio works.
The answer: the most ordinary radio receiver contains:
the oscillating contour, connected with
antenna, united with
chain contour, that consists of
the detector
condensator
telephone-dynamic
The question: It explains the contents of the radio receiver (Neznayka is
wondered and begins to ask radio master, how does the sound without
cables reach us)?
The answer: Represents the oscillating contour – one of he main
knots of radio receiver (radio master says that the heart of radio is
the contour that consists of inductive spool and condensator).
The question: What is the main knot in the radio receiver, and what
can be compared with it’s in the mechanic watches?
The answer: The condensator consists of two conductors,
divided by the layer of isolator, which thickness is small in
compare with conductor’s size. To charge the condensator we
have to join it’s conductors with the generator’s poles. The
plates charges are similar in the count meaning, but opposite by
the sign. This is the image expression of the condensator’s
charging process. The signs on it’s sides mean hoarded
charges.
The question: What is the condensator, and how does it charge?
The answer: By the condensator’s spacing through the inductive
spool, in the created chain the electric oscillations appear. In the
process of these oscillations goes the periodic transformation of the
energy of the electric field in the energy of the magnetic field and
inversely. It explains how the oscillating contour acts (the
mechanism of its В«swingingВ»).
The question: how does the oscillating contour works?
The answer: 1) thanks to short waves from 10m to 100meters,
that spread on long distances only by frequent reflections from
the ionosphere and the surface of the Earth, it is possible to
realize the radio connection on every distance between the
radio stations on the Earth.
2) On the limited distances the connection is realized on long
waves, longer than 100meters.
3) On the distances of the direct evidence and for the
connection with the space ships the extremely short waves are
used, they are less than 10m.
The fifth picture represents the multitude of radio waves that
В«entangleВ» the Earth.
The question: Thanks to what nature phenomenon the distant radio
connection goes?
The answer: The phenomenon of the forced oscillations’ amplitude
rough increasing by the equality of the forcing power frequencies
and the personal oscillating system frequency is called the
resonance.
The sixth picture explains the phenomenon of
mechanical resonance (each harp’s string responses it’s personal
sound).
The question: What is called the resonance?
The answer: The seventh picture helps to understand the
process of oscillating contour tuning in the resonance with
the definite wave (we roll the condensator’ knob and
change the inductive spools: we attain so that the personal
frequency of contour coincides with the frequency of the
necessary radio station wave. The contour doesn’t permit:
their frequency is not that one and they are
В«unnecessaryВ»).
The question: How can we tune the radio receiver on the necessary wave?
The answer: the eighth picture illustrates the transformation of
sound waves in the oscillations of the electric current and
inversely
The question: What wave reforms are represented on this picture?
The answer: Modulation–is the change of the high frequency
oscillations (the carrying frequency of the electric-magnetic
waves) with help of low (sound) frequency electric oscillations
in the oscillation amplitude.
the graphic of the high frequency oscillations. Such frequency
is called the carrying frequency.
the graphic of the sound frequency oscillations, i.e.
modulating oscillations.
the graphic of the oscillations, modulated in the amplitude.
The ninth picture acquaints us with the process of wave
modulation.
The question: What is called the modulation process?
The answer: the tenth picture acquaints with modulated wave.
The question: What electric-magnetic wave is demonstrated?
The answer a: the allotting of the low frequency oscillations from the modulated
high frequency oscillations. The signal, got in the result of detection, matches the
sound signal, that influenced on the transmitter microphones. The eleventh picture
is the analogy of the received electric-magnetic waves detection (the man, named
The Detector – D, chops with an axe the negative semi-periods of the received
radio waves).
The answer b : the twelfth picture gives the presentation of the process of
modulated oscillations dividing into high frequency and low frequency oscillations;
for high frequency oscillations as the analog the Mother is imagined, for low
frequency oscillations – the child; therefore the modulated oscillations are
presented by us (from the right) as the flow of women-passengers carrying their
children; in the building of the railway station D (detector) the flow dividing goes:
the children (low frequency oscillations) continue their way straightly, but mothers
(high frequency oscillations) turn into the perpendicular platform.
The question a: What is called the detection?
The question b: Tell about detection through the illustration.
The answer: The better radio waves receiving has the man, sitting in
the open area. The man in the building has more feeble receiving,
because the radio wave has some attributes:
the absorption by different isolators.
the reflection from different metal plates.
the refraction on the boundary of isolator.
The thirteenth picture shows the permeation ability of radio waves.
The question: What can be said about the radio waves percolation
possibilities? Which of the listeners: a man, sitting in the open area
or a man, sitting in the ferro-concrete building – has the better radio
wave receiving?
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