Prepared By: Shakil Raiman
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Waves are a means of transferring energy and information from
one place to another.
These transfer takes place with no matter being transferred.
For example, energy can be carried by a water wave generated
by a boat out at sea to the shore, or by a sound wave from the
loudspeaker to an audience’s ears.
The most common waves found in daily life are water waves,
sound and electromagnetic waves.
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Two types of waves:
 Transverse wave
 Longitudinal Wave
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A transverse wave is a wave in which the vibrations
of the particles are at right angles to the direction
of propagation of the wave.
EXAMPLES OF TRANSVERSE WAVES:
 Microwaves, radio waves, infra-red, visible light, ultra-
violet, X-rays and -rays are called electromagnetic
waves. All these waves are transverse waves. Another
example is water wave.
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A longitudinal wave is a wave in which the
vibrations of the particles are parallel to the
direction of propagation of the wave.
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EXAMPLES OF LONGITUDINAL WAVES:
 Sound wave
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Amplitude: The amplitude of a wave is the maximum
displacement of a particle from its resting position. SI unit is
metre (m).
 Wavelength: The wavelength of a wave is the minimum
distance at which the wave repeats itself. It can also be taken
as the distance between two successive crests ( or troughs).
It is denoted by  (lambda). SI unit is metre (m).
 In case of longitudinal wave, wavelength is the distance between
two successive centres of compression (or rarefaction)
Period or Time Period: The period of a wave is the time taken
for one complete vibration of a particle. It is also the time taken
to produce one complete wave. It is denoted by T. SI unit is
second (s).
 Frequency: The frequency of a wave is the number of complete
waves produced per second. It is denoted by f. SI unit is hertz
(Hz).
 The relationship between period and frequency is:
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1
f 
T
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The speed, v, of a wave is the distance traveled by the wave in
one second.
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The wave moves by a distance of one wavelength () is one
period (T), so the wave speed (v) is:
v
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As,
f 
1
T
dis tan ce 

time
T
so, v = f
A ripple tank is a
shallow glass tank of
water used in schools
and colleges to
demonstrate the basic
properties of waves.
 When the motor is
turned on the wooden
bar vibrates and
produce waves.
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A ripple tank
can be used
to produce
waves to
investigate
the
wavelength,
amplitude
and
frequency of
a wave.
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Reflection is the change in direction of a wavefront at an
interface between two different media.
Laws of reflection:
 The incident ray, normal and the reflected ray all lie on same plane.
 The incident angle (i) = the reflected angle (r)
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Normal is a line drawn at right angles to the surface (at the
point of incident ray).
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Refraction is the change in direction of a wave due to a
change in its transmission medium.
Laws of refraction:
 The incident ray, normal and the refracted ray all lie on same plane.
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sin i
 const .  refractive _ index
sin r
Diffraction is the spreading of waves while passing through
narrow gap.
 If the gap is close to the wavelength of the wave diffraction is
most.
 Examples of diffraction include sound waves that diffract as
they pass through doorways.
 Diffraction also happens when waves pass a single edge.
Radio waves are diffracted as they pass over hills.
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Wish you all very good luck and excellent
result.