WAVES
The simplest explanation of a wave is a
oscillation which spreads to its adjacent
regions. Electromagnetic waves, sound
waves, seismic waves, water waves and
other types of waves have characteristic
properties as well as common properties.
Transverse waves- These are the waves in
Which particles of the medium vibrate about
Their mean position in a direction perpendicUlar to the direction of propagation of the
Disturbance.
e.g. solids.
Longitudinal waves –These are the waves in
Which particles of the medium vibrate about
Their mean position along the direction of
Propagation of the disturbance.
e.g. solids,liquids & gases.
There are two types of waves transverse
and longitudinal.
Transverse waves are waves in which
the vibrations are perpendicular to the
direction of movement wave, the most
important example of these are the
waves in the electromagnetic spectrum
(light waves, radio waves…). Longitudinal
waves are waves in which the vibrations
are parallel to the direction of
movement of the wave. Examples
include sound waves and seismic pwaves.
The frequency of a vibrating object is the rate at
which it oscillates. The higher the frequency the
faster the oscillations are occurring. Frequency is
therefore shown in the formula ƒ=1/T where ƒ
is frequency and T is the time taken for a
complete oscillation to its original position.
Waves are characterised by their wavelength,
the distance travelled in one complete cycle of
wave oscillation. The wavelength of a wave is the
distance along the direction of movement from a
wave crest to the next wave crest. The SI unit of
wavelength is the metre.
Graphical representation of wave
OSCILLATION
Oscillation is the repetitive variation, typically in time, of
some measure about a central value (often a point of
equilibrium) or between two or more different states. Familiar
examples include a swinging pendulum and AC power. The
term vibration is sometimes used more narrowly to mean a
mechanical oscillation but sometimes is used to be
synonymous with "oscillation." Oscillations occur not only in
physical systems but also in biological systems and in human
society.
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rights reserved.
Grandfather Clock
This grandfather clock uses a pendulum
to keep accurate time. The pendulum
swings back and forth under the force of
gravity.
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Microsoft ® Encarta ® 2008. © 1993-2007 Microsoft Corporation. All rights
reserved.
Freefall
Falling objects accelerate in response to the force exerted
on them by Earth’s gravity. Different objects accelerate at
the same rate, regardless of their mass. This illustration
shows the speed at which a ball and a cat would be
moving and the distance each would have fallen at
intervals of a tenth of a second during a short fall.
EXAMPLES OF WAVES
TYPES OF WAVES
There are three basic types of waves -:
(i) Mechanical Waves – The waves which require a
Mechanical medium for their propagation are called
Mechanical waves or elastic waves.For their propagation,
The medium must possess the properties of inertia &elasticity.
For example , water waves,sound waves,etc.
(ii) Electromagnetic waves- The waves which travel in form
Of oscillating electric & magnetic fields are called electroMagnetic waves.
For e.g. visible light ,radio waves,etc.
(iii)Matter waves-The waves associated with microscopic
Particles ,such as electrons ,protons,neutrons,atoms,molecules
Etc.,when they are in motion,are called matter waves or
De- broglie waves.
WAVELENGTH
It is distance covered by a wave during the time a particle
Of the medium completes one vibration about its mean
Position.
WAVE VELOCITY-It is distance by wave in one second.
Application of wave velocityRadar gun
Radar guns are used to detect speeding
motorists. Here, a gun transmits waves at a
given frequency (shown in blue) toward an
oncoming car. Reflected waves (shown in red)
return
to the gun at a different frequency,
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depending on how fast the car being tracked
is moving. A device in the gun compares the
transmission frequency to the received
frequency to determine the speed of the car.
In this case, the high frequency of the
reflected waves indicates the motorist in the
red car is speeding and is probably about to
receive a ticket.
RADAR GUN