APPLIED PHYSICS
I. THEORIES AND PRINCIPLES
A.Wave Motion and Sound Waves
Wave – is a periodic disturbance. These are produced in all forms of matter and even in empty
space where ordinary matter does not exist.
cre st
)
Wavelength (λ
Amplitude
v
trough
Types of Waves in Matter:
1. Transverse
– a wave in wave
which the vibration direction is perpendicular to the
direction of the wave propagation. Examples are water waves, waves in strings under
tension, electromagnetic waves – light and radio waves.
2. Longitudinal (or Compressional) wave – a wave in which the vibration direction is
parallel to the direction of the wave propagation. Examples are sound waves, waves in
rods and in vibrating helical spring.
Wave Terminologies:
1. Period of vibration (T) – is the time taken for a particle to move through a complete
cycle.
2.
– the number of such vibrations executed by the particle each
Frequency of vibration (f)
3. Crest
second.– the top points on the wave.
4. Trough – the bottom points on the wave.
5. Amplitude (A) – the maximum displacement from their normal position of the particles
that oscillate back and forth.
6.Wavelength () λ – is the distance between two successive points in a wave.
7. Standing wave – a stationary wave pattern formed in a medium when two sets of
identical wave pass through the medium in opposite directions.
Wave Properties:
1.
Reflection – the property of wave which occurs when a wave strike an object or comes
to a boundary or another medium and is at least diverted back into the original medium.
2. Refraction
– the wave property which occurs when a wave crosses a boundary into
another medium its speed generally changes because the new material has a different
characteristic. Entering the medium obliquely (at an angle), the transmitted wave moves
in a direction different from that of the incident wave.
3. Diffraction – the property of wave to bend around an edge of an object but is unrelated
to refraction.
1
, 4. Dispersion – the property of a wave whereby waves of different frequency spread apart
from each other.
5. Interference – the wave phenomena that occur when two or more waves overlap in the
same region of space.
Wave Equations:
1. The velocity of the wave
V=λf
Where: V is the velocity in m/sec
λ is the wavelength in m
f is the frequency in Hz
2. The Period (T) – is the reciprocal of the frequency.
1
T= f
Where: T is the period in seconds
3. The Velocity of the Longitudinal Waves in Solids and Liquids
E
V = ρ
Where: E is the modulus of elasticity in Pascal
ρ is the density in kg/m
4. The Velocity of the Longitudinal Waves in Gases
V= kRT
Where: R is gas constant in KJ/kg
R
R= And R= 8.314 J-mol/K
MW
MW is the molecular weight in kg/mol
k is a constant
k=Cp/Cv=1.4→for air, oxygen and nitrogen
T is absolute temperature in K
5. The Velocity of the Transverse Waves on Stretched Spring or Wire
T
V = ρlinear
Where: T is the tension in N
ρlinear = mass/length; it is the linear density in N/m
Laws of Vibrating String Under Tension
String under tension at a certain vibration frequency will resonate. Meaning it will vibrate with
large amplitude in vibration patterns. These similar vibration patterns are called standing
waves.
2
, If the string has n segments long, then
1 V
L=n λ And fn=n
2 2L
Where: n is the number of segments
fn is the frequency of n segments
L is the length of the string
V is the velocity
Fundamental Frequency – is the lowest natural frequency.
V
fT= Where: n = 1 → fundamental frequency
2L
All the other natural frequencies are integral multiple of the fundamental frequency
V n T
fn=n = =nf1 (For n = 1, 2, 3 …)
2L 2L ρlinear
The set of frequencies: f1, f2 = 2f1, f3 = 3f1 … are called harmonic series.
B. The Nature of Sound
Sound – is a disturbance or vibration whose energy must be communicated into a medium.
Classification of sound waves:
1. Music – a sound of one regular vibration or more definite frequencies.
2. Noise – a sound of irregular vibration or of no definite range of frequency.
Three physiological characteristics of sound:
1. Pitch – is the highness or lowness of a note or tone.
2. Intensity – is also known as the “loudness” of sound. It is the rate at which sound energy
flows through a unit area.
3. Quality – also known as timbre in which depends on the waveform or vibration from the
source.
Sound Terminologies:
1. Echo – is the reflected sound.
2. Reverberation – the successive echoes that can be heard.
3. Audible Range – the hearing range of human being between 10 Hz to 20,000 Hz.
4. Ultrasonic – sound that has a frequency too high to be heard by human ear, above 20,000
Hz. – sound that has a frequency too low to be heard by human ear, below 20 Hz.
5.
Infrasonic
6.Shock Wave – the cone-shaped wave made by an object moving at supersonic speed
through a fluid.
7. Sonic Boom – is the loud sound resulting from the incidence of a shock wave.
8. Rarefaction – rarefied region, or region of lessened pressure, of the medium through
which a longitudinal wave travels.
9. Beats – the alternations of maximum and minimum sound intensity produced by
superposition of two sound waves of slightly different frequencies.
10. Resonance – is the response of a body when a forcing frequency matches its natural
frequency.
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I. THEORIES AND PRINCIPLES
A.Wave Motion and Sound Waves
Wave – is a periodic disturbance. These are produced in all forms of matter and even in empty
space where ordinary matter does not exist.
cre st
)
Wavelength (λ
Amplitude
v
trough
Types of Waves in Matter:
1. Transverse
– a wave in wave
which the vibration direction is perpendicular to the
direction of the wave propagation. Examples are water waves, waves in strings under
tension, electromagnetic waves – light and radio waves.
2. Longitudinal (or Compressional) wave – a wave in which the vibration direction is
parallel to the direction of the wave propagation. Examples are sound waves, waves in
rods and in vibrating helical spring.
Wave Terminologies:
1. Period of vibration (T) – is the time taken for a particle to move through a complete
cycle.
2.
– the number of such vibrations executed by the particle each
Frequency of vibration (f)
3. Crest
second.– the top points on the wave.
4. Trough – the bottom points on the wave.
5. Amplitude (A) – the maximum displacement from their normal position of the particles
that oscillate back and forth.
6.Wavelength () λ – is the distance between two successive points in a wave.
7. Standing wave – a stationary wave pattern formed in a medium when two sets of
identical wave pass through the medium in opposite directions.
Wave Properties:
1.
Reflection – the property of wave which occurs when a wave strike an object or comes
to a boundary or another medium and is at least diverted back into the original medium.
2. Refraction
– the wave property which occurs when a wave crosses a boundary into
another medium its speed generally changes because the new material has a different
characteristic. Entering the medium obliquely (at an angle), the transmitted wave moves
in a direction different from that of the incident wave.
3. Diffraction – the property of wave to bend around an edge of an object but is unrelated
to refraction.
1
, 4. Dispersion – the property of a wave whereby waves of different frequency spread apart
from each other.
5. Interference – the wave phenomena that occur when two or more waves overlap in the
same region of space.
Wave Equations:
1. The velocity of the wave
V=λf
Where: V is the velocity in m/sec
λ is the wavelength in m
f is the frequency in Hz
2. The Period (T) – is the reciprocal of the frequency.
1
T= f
Where: T is the period in seconds
3. The Velocity of the Longitudinal Waves in Solids and Liquids
E
V = ρ
Where: E is the modulus of elasticity in Pascal
ρ is the density in kg/m
4. The Velocity of the Longitudinal Waves in Gases
V= kRT
Where: R is gas constant in KJ/kg
R
R= And R= 8.314 J-mol/K
MW
MW is the molecular weight in kg/mol
k is a constant
k=Cp/Cv=1.4→for air, oxygen and nitrogen
T is absolute temperature in K
5. The Velocity of the Transverse Waves on Stretched Spring or Wire
T
V = ρlinear
Where: T is the tension in N
ρlinear = mass/length; it is the linear density in N/m
Laws of Vibrating String Under Tension
String under tension at a certain vibration frequency will resonate. Meaning it will vibrate with
large amplitude in vibration patterns. These similar vibration patterns are called standing
waves.
2
, If the string has n segments long, then
1 V
L=n λ And fn=n
2 2L
Where: n is the number of segments
fn is the frequency of n segments
L is the length of the string
V is the velocity
Fundamental Frequency – is the lowest natural frequency.
V
fT= Where: n = 1 → fundamental frequency
2L
All the other natural frequencies are integral multiple of the fundamental frequency
V n T
fn=n = =nf1 (For n = 1, 2, 3 …)
2L 2L ρlinear
The set of frequencies: f1, f2 = 2f1, f3 = 3f1 … are called harmonic series.
B. The Nature of Sound
Sound – is a disturbance or vibration whose energy must be communicated into a medium.
Classification of sound waves:
1. Music – a sound of one regular vibration or more definite frequencies.
2. Noise – a sound of irregular vibration or of no definite range of frequency.
Three physiological characteristics of sound:
1. Pitch – is the highness or lowness of a note or tone.
2. Intensity – is also known as the “loudness” of sound. It is the rate at which sound energy
flows through a unit area.
3. Quality – also known as timbre in which depends on the waveform or vibration from the
source.
Sound Terminologies:
1. Echo – is the reflected sound.
2. Reverberation – the successive echoes that can be heard.
3. Audible Range – the hearing range of human being between 10 Hz to 20,000 Hz.
4. Ultrasonic – sound that has a frequency too high to be heard by human ear, above 20,000
Hz. – sound that has a frequency too low to be heard by human ear, below 20 Hz.
5.
Infrasonic
6.Shock Wave – the cone-shaped wave made by an object moving at supersonic speed
through a fluid.
7. Sonic Boom – is the loud sound resulting from the incidence of a shock wave.
8. Rarefaction – rarefied region, or region of lessened pressure, of the medium through
which a longitudinal wave travels.
9. Beats – the alternations of maximum and minimum sound intensity produced by
superposition of two sound waves of slightly different frequencies.
10. Resonance – is the response of a body when a forcing frequency matches its natural
frequency.
3
