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1. Physics: Waves
By: Daisy Sowah, Neel Shah, Brian Vlaar and Nii
Adjei Ala-Lomo

2. What are waves?
• Wave motion is a form of disturbance
which travels through a medium due
to the repeated periodic motion of
the particles of the medium about
their mean positions, the motion being
handed over from one particle to
another.

3. Types of Waves
which can be
or propagated only in
medium are called
mechanical waves.
The waves which d
require a medium
propagate are ca
electromagnetic

4. Types of wave
motion
When the particles of the
medium vibrate about their
mean positions in a direction
perpendicular to the direction of
propagation of disturbance, the
wave motion is called the
transverse wave motion.
When the particles of the
medium vibrate about their
mean positions in the direction
of propagation of disturbance,
the wave motion is called the
longitudinal wave motion

5. Some Wave Terms
Displacement –
Distance and
direction from
equilibrium
position
Amplitude –
Maximum
displacement of
vibrating particle
from equilibrium
position
Wave Period –
Time for one
wave to pass a
fixed point
Intensity is the
measure of how
much energy a
wave is carrying.
It can also be
defined as the rate
of flow of energy
per unit area at
right angles to the
direction of travel
of a wave (W/m)
Frequency –
Number of
complete waves
passing a point
each second. (Hz)
Wave cycle - From one
maximum
displacement to the
next maximum
displacement
Wavelength – The least
distance between 2
adjacent vibrating
particles ie. 2 peaks or
troughs

6. Wave Phases
•
•
•
•
•
Phase Difference is the amount by
which two cyclical motions of the
same frequency, are out of step
with each other. It can be
measured in degrees, radians, or
seconds of time.
leading phase refers to a wave that
occurs "ahead" of another wave of
the same frequency.
Lagging phase refers to a wave
that occurs "behind" another wave
of the same frequency.
When two signals differ in phase by Phase Difference
90 or +90 degrees, they are said to
be in phase quadrature .
When two waves differ in phase by
180 degrees (-180 is technically the
same as +180), the waves are said
to be inphase opposition .
Coherent waves
are waves with a
constant phase
difference. (Note:
They don't have
to be in phase for
this to be true.)
They will have the
same frequency
and wavelength
(they are normally
produced from
one source).

7. Diffraction
•
•
•
•
A wave will diffract (spread out)
as it goes through a gap or past
an obstacle but the wavelength
remains the same before and
after the gap.
The nearer the slit size is to the
wavelength, the more the wave
will diffract.
The smaller the gap the greater
the diffraction.
The longer the wavelength the
greater the diffraction.

8. Interference and
Superposition
Interference may be
Principle of two waves meet they will interfere and superpose. After they have passed they as
described
When
Superposition: Whenoriginal forms. This is true if they are coherent or not.
the superposition of
return to their
two or At the waves
more point they meet, the two waves will combine to give a resultant wave whose from 2
waves
of the same type intensity) may be greater or less than the original two waves. coherent sources
amplitude (or
meet at a point, the displacement can be found by adding the two displacements
The resultant
resultant
together
displacement of the
waves is equal to
the vector sum of
their individual
displacements at
that point.
.
If two waves of the same type and the same frequency combine so that the crest of
one coincides with the trough of the other, they will completely cancel each other out.
This is called destructive interference.
Alternatively, the two waves could combine when their crests coincide; then there
would be constructive interference and the resultant amplitude would be equal to the
sum of the separate amplitudes:

9. Thank you for
you time