2. WHAT IS A SOUND WAVE?
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
2
2
0
X
X
A sound wave is the pattern of disturbance
caused by the movement of energy traveling
through a medium (such as air, water or any
other liquid or solid matter) as it propagates
away from the source of the sound. Sound
waves are created by object vibrations and
produce pressure waves, for example, a
ringing cellphone.
3. C O M P R E S S I O N I S A R E G I O N I N
A L O N G I T U D I N A L WAV E W H E R E T H E
PA R T I C L E S A R E C L O S E S T
T O G E T H E R . A R A R E FA C T I O N I S A
R E G I O N I N A L O N G I T U D I N A L WAV E
W H E R E T H E PA R T I C L E S A R E
F U R T H E S T A PA R T . T H E R E G I O N
W H E R E T H E M E D I U M I S C O M P R E S S E D
I S K N O W N A S C O M P R E S S I O N A N D
T H E R E G I O N W H E R E T H E M E D I U M I S
S P R E A D O U T I S K N O W N A S A
R A R E FA C T I O N
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
3
2
0
X
X
5. W H AT I S A W AV E L E N G T H ?
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
5
2
0
X
X
The distance traveled by
the wave during one
complete oscillation is
called the wavelength of the
wave. The SI unit of
wavelength is a meter(m).
6. FREQUENCY
• Frequency of a sound wave when sound is propagated
through a medium, the density of the medium oscillates
between a maximum value and a minimum value
• The change in density from the maximum value to the
minimum value, then again to the maximum value, makes
one complete oscillation.
• The number of such oscillations per unit time is the
frequency of the sound wave.
• If we can count the number of the compressions or
rarefactions that cross us per unit time, we will get the
frequency of the sound wave. Its SI unit is hertz (symbol,
Hz).
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
6
2
0
X
X
7. H E I N R I C H R U D O L P H H E R T Z
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
7
2
0
X
X
Ø HE WAS BORN ON 22ND FEBRUARY 1857.
Ø HE STUDIED IN HAMBURG GERMANY
AND EDUCATED AT UNIVERSITY OF
BERLIN.
Ø HE CONFIRMED J.C MAXWELL
ELECTROMAGNETIC THEORY BY HIS
EXPERIMENT.
Ø HE THEN LAID FUTURE DEVELOPMENT
OF RADIO, TELEPHONE, TELEGRAPH,
TELEVISION.
Ø HE EVEN DISCOVERED
PHOTOELECTRIC EFFECT WHICH WAS
LATER EXPLAINED BY ALBERT EINSTEIN.
Ø S I UNIT OF FREQUENCY WAS NAMED
BY HERTZ
This Photo by Unknown Author is licensed under
CC BY-NC-ND
8. PITCH
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
8
2
0
X
X
• How the brain interprets the frequency of an
emitted sound is called its pitch
• When Frequency is high, pitch is high
When Frequency low, pitch is low
• Higher pitch corresponds to a greater number of
compressions and refractions passing a fixed
point per unit time.
12. SPEED
P
R
E
S
E
N
T
A
T
I
O
N
T
I
T
L
E
12
2
0
X
X
• Speed of sound is defined as the distance which appoint on a wave such
as a compression or a rarefaction travels per unit time. We know, Speed,
v=distance/time
• Here λ is the wavelength of the sound travelled by the sound wave in one
rime period (T) of the wave.
• Thus, v=λ v. That is, speed=wavelength× frequency.
• The speed of sound remains almost the same for all frequencies in a
given medium under the same physical conditions.
• The amount of sound energy passing each second through unit area is
called the intensity of sound
• . We sometimes used the term loudness and intensity, But they but they
are not the same. Loudness is the measure of the response of the ear to
the sound. Even when two sounds are of equal intensity, We may hear one
as Louder Than The Other simply because our ear detects it better.
13. • Sound propagates through a medium at a finite
speed
• Speed of the sound depends on the medium it
travels through
• It decreases from solid to gaseous state
• In any medium if the temperature increases,
the speed of the sound too increases.
15. SONIC BOOM
● What is a Sonic Boom?
● Supersonic sound
● What causes it?
16. WHAT IS A
SONIC BOOM?
A sonic boom is a sound
associated with shock
waves created, when an
object travels through the
air faster than the speed of
sound.
17. SUPERSONIC
SOUND!
Supersonic sound is produced when,
objects travel at a speed greater
than the speed of sound.
Example: Jet Aircrafts, Bullets etc.
18. HOW IS A SONIC
BOOM CAUSED ?
When a sound producing
source moves with a
speed higher than that
of sound, it produces
shock waves in the air.
This results in a sonic
boom.
