Definition of Sound Waves and Their Nature

Definition of Sound Waves and Their Nature
Waves: Definition, Sound, Kind, Type, Nature, Formulas and Examples Is a disturbance (vibration) that propagates in a medium, which carries energy from one place to another.

Definition of Waves
Waves are a disturbance (vibration) that propagates in a medium, which carries energy from one place to another. In the wave that propagates is the wave, not the intermediate substance. The ideal form of a wave will follow the sinusoid movement. In addition to electromagnetic radiation, and possibly gravitational radiation, which can travel through a vacuum, waves are also present in the medium (which due to changes in shape can produce flexible recovery forces) where they can travel and can transfer energy from one place to another without causing medium particles move permanently; i.e. there is no mass transfer. Instead, each specific point oscillates around one particular position.
Waves are defined as vibrations that propagate through the medium, in the form of solids, liquids, and gases. Waves are vibrations that travel. The ideal form of a wave will follow the sinusoid movement. In addition to electromagnetic radiation, and possibly gravitational radiation, which can travel through a vacuum, waves are also present in the medium (which due to changes in shape can produce flexible recovery forces) where they can travel and can transfer energy from one place to another without causing medium particles move permanently; i.e. there is no mass transfer. Instead, each specific point oscillates around one particular position.

A medium is called:
linear if different waves at all specific points in the medium can be added up
limited if limited, otherwise called infinite
uniform if the physical characteristics don't change at different points
isotropic if the physical characteristics are "the same" in different directions

Types of Waves
Judging from the conductor or also the medium traversed by waves, we can distinguish There are two kinds of waves, namely mechanical waves and electromagnetic waves.
Waves consist of two types, namely transverse waves (transverse waves) and longitudinal waves (longitudinal waves).

Mechanical waves
Mechanical waves are waves which in their propagation require a medium or conductor to propagate. Mechanical wave medium can also be a solid, liquid, or gas. Sound or sound is one example of mechanical waves that can propagate through the solid, liquid or gas. For example, mechanical waves are waves on a rope, waves on a spring, waves on the surface of water.

Transverse waves
Transverse waves are waves that vibrate from each point of the particle in the medium (conduit), perpendicular to the direction of wave propagation. For example, light waves, surface waves, and waves on a rope. To see the vibrational direction of the transverse wave, you can use a rope by means of one end of the rope tied while the other end is left free. In the case of the wave wave, the movement of the hand up and down will result in energy in the rope. The energy vibrates the area across the rope so that the area around it also vibrates up and down, and so on until the end of the rope. In transverse waves, a wavelength is the same distance as a hill wave plus a valley wave.
The characteristic of transverse waves is that there is a hill wave and a valley wave and a wavelength (lamda) is the same distance as a wave hill with a valley wave. . For example, waves in the spring (slinki) and light waves. When the slinki is moved forward and backward, then the slinki will be formed densely and also stretched. In a longitudinal wave, one wavelength is the same distance as a density and a gap is added. Characteristics of longitudinal waves, there are densities and distances and one wavelength is the same distance as one density plus one distance.
Transverse waves are waves whose direction is perpendicular to the direction of their vibrations. A wave can be grouped into trasnversal waves if the particles of the medium vibrate up and down in a direction perpendicular to the wave motion. Examples of transverse waves are rope waves. When we move the rope up and down, it appears that the rope moves up and down in a direction perpendicular to the direction of wave motion. Transverse waveforms look like the image below.

Transverse waves Transverse waves2
Based on the picture above, it appears that the wave propagates to the right in the horizontal plane, while the vibrational direction fluctuates in the vertical plane. The dashed line drawn in the middle along the wave propagation direction represents the balanced position of the medium (such as a rope or water). The highest point of the wave is called the peak, while the lowest point is called the valley. Amplitude is the maximum height of the peak or the maximum depth of the valley, measured from the equilibrium position. The distance of two equal and consecutive points on a wave is called wavelength (called lambda - greek letters). Wavelength can also be considered as distance from peak to peak or distance from valley to valley.

Longitudinal Waves
Electromagnetic waves are waves that can propagate without the need for delivery and are transverse waves. But these electromagnetic waves are field waves, not mechanical waves (matter). In electromagnetic waves, the electric field E is always perpendicular to the direction of the magnetic field B and both are perpendicular to the direction of the wave propagation. Electromagnetic wave interference occurs due to electric and magnetic fields, therefore electromagnetic waves can propagate in a vacuum.
In addition to transverse waves, there are also longitudinal waves. If in the transverse wave the direction of the vibrations of the medium is perpendicular to the direction of propagation, then in the longitudinal wave, the direction of the vibrations of the medium is parallel to the direction of the wave propagation. If you are confused by this explanation, imagine the vibration of a spring. Look at the picture below.

Longitudinal Waves
In the picture above it appears that the direction of vibration is parallel to the direction of wave propagation. A series of densities and stretches travel along a spring. Density is an area where spring coils are close to each other, while strain is an area where spring coils find one another. If the transverse wave has a pattern of peaks and valleys, then the longitudinal wave consists of dense and stretch patterns. Wavelength is the distance between sequential densities or sequential strains. What is meant here is the distance from two equal and consecutive points at the density or strain (see example in the picture above).
One example of logitudinal waves is sound waves in the air. Air as a medium for sound wave propagation, close and stretch along the direction of propagation of air waves. Unlike water waves or rope waves, sound waves we cannot see using the eyes. You like listening to music right? Try touching the loudspeaker while you are playing a song. The greater the volume of the song playing, the loudspeaker louder vibrates. If you pay close attention, the loudspeaker vibrates back and forth. In this case the loudspeaker functions as a source of sound waves and emits sound waves (longitudinal waves) through the air medium. Regarding the full sound wave will be studied on a separate subject.

Various kinds of waves
Wave According to the direction of vibration:
Transverse waves are waves whose vibrational direction is perpendicular to the direction of propagation. Example: waves on a rope, surface waves, light waves, etc.
Longitudinal waves are waves whose vibrational directions are parallel or coincide with the direction of propagation. Example: sound waves and waves on a spring.

Waves According to their Amplitude and Phase

Waves According to their Amplitude and Phase
A traveling wave is a wave whose amplitude and phase are the same at each point the wave passes.
Stationary waves are waves whose amplitudes and phases change (not the same) at each point the wave travels.
Wave According to its intermediary medium:
Mechanical waves are waves which in their propagation require intermediary media. Almost all waves are mechanical waves.
Electromagnetic waves are waves which do not require intermediate propagation medium. Example: gamma rays (γ), X rays, ultra violet rays, visible light, infrared, radar waves, TV waves, radio waves.

Stationary Waves (silent)
This stationary wave can occur due to interference (the merging of two waves, namely the incoming and reflected waves). Reflected waves that occur can be in the form of reflections with a fixed tip and can also be reflected reflections are a continuation of the incoming wave (fixed phase), but if the reflection occurs at a fixed end, the reflected wave undergoes a phase reversal (different 1800 phases) to the incoming wave.

Wave Properties
In this discussion we will study the properties of waves which include reflection, refraction, disperse, interference, diffraction, and polarization.

Wave Reflection (Wave Reflection)
Wave Reflection
The reflection of waves in the ripple tank, in this reflection obtained a circle wave whose center is the source of the S wave. The reflected waves generated by the straight plane are also in the form of a circle S as the center of the circle. The distance S to the reflecting plane is the same as the distance s to the reflected plane.
According to Snellius's Law, dating waves, reflected waves, and normal lines are in one plane and the dating angle will be the same as the reflected angle, as shown in the following figure:
For two or three dimensional waves such as water waves, we are familiar with the terms light waves and wavefronts.

Wave face
Front wave (Front wave) is defined as a place where the dots have the same phase in the wave, in the picture next to this circle shows the circle is the wave face. The distance between adjacent wavefronts is equal to one wave (λ). A ray is a line drawn in a direction perpendicular to the wavefront.

Front wave
If the circular waves propagate continuously in all directions then at great distances from the source of the wave, we will see the wave face that is almost straight, as well as waves of sea water until the beach. Such wavefronts are called plane waves.

Sound Waves
In the previous chapter we learned about wave equations
as presented in equation (2.9) and equation (2.19). In this section we will specifically study the problem of sound waves. The study will begin with a description of the application of Hooke's law and Newton's law in the case of propagation of longitudinal waves in the trunk, only then will the same principle be used to discuss sound wave propagation in the fluid where in this case we will use the gas medium as a study material. 3.1. Sound Propagation in Bars The reason why we first examine the propagation of longitudinal waves in rods before discussing the same thing in the gas medium is because the principles of elasticity are much easier to understand, as well as with relatively simplified mathematical descriptions.
Suppose we have a bar with a cross-body A and density ρ as shown in Figure (3.1). In this case we assume that the rod is given a stress disturbance at one end, so that the particles in it experience a deviation from the equilibrium position and then wave propagation occurs along the rod in the direction parallel to the direction of the constituent particles of the rod. .
We can view Figure (3.1) as a state where a force ………… works at a cross-section and points normally along the stem. Then according to Hooke's law,

Definition of Intensity of Physical Material

Definition of Intensity of Physical Material
 "Physics Material" Definition of intensity & (Formula - Sound Intensity Level - Application of Sound Waves)
For a discussion of physical material which includes things such as the definition of intensity, formulas, sound intensity levels and the application of sound waves, in order to better understand the review below.

Definition of Intensity
In this case the word intensity is defined as the energy transferred in each unit of time and not a unit of area, and it is known that the energy of each unit of time is the understanding of power, then the intensity can also be said to be the power of each unit of area. So that the intensity can be formulated mathematically is as below:

"Physics Material" Definition of intensity & (Formulas - Sound Level Intensity - Application of Sound Waves)
I = P / A

Known:
I = Sound intensity (W / m2)
P = Energy every time or power (W)
A = Area (m2)
If isotropic or better known by the source of the sound that emits the sound in all directions the same magnitude.
The area being addressed has a similarity in the surface area of a ball. So that the equation on intensity can be written like:
I = P / 4πR2

Sound Intensity Level
The sound intensity level is a logarithm that compares the sound intensity with the threshold intensity. So the level of sound intensity can be formulated mathematically is as below:
TI = 10 log l / l


Known:
TI = Sound intensity level (dB)
I = Sound intensity (W / m2)
lo = intensity of human hearing threshold (10˄-12 W / m2)
And for example n pieces at the sound source such as there are n sirens that are turned on simultaneously, then the level of intensity of the sound can be written with:
Tln = Tl1 + 10 log n

If you hear at two different points of distance, the amount of sound intensity at the second point can be written with:
TI = Tl1 + 20 log (RA / RB)

Application of Sound Waves
Utilization of ultrasonic waves is very much for various purposes and needs such as:
To measure the depth of the sea.
In glasses, especially blind glasses (there is a sending device and an ultarsonic receiver).
In medical devices such as ultrasonography (USG).
Benefits of Fast Sound Creeping
The benefits and functions of sound propagation in daily life are as follows:

At this fast sound wave propagation can be used by fishermen to be able to know the time of day and night.
At night, the sound will be more clearly heard than during the daytime, and this is because the air density that occurs at night is denser than during the daytime.

Benefits of Resonation
The benefits of resonance in everyday life are as in musical instruments as follows:
Drum
Beduk
Flute and others
Benefits of Sound Reflection
The benefits of sound reflection in everyday life are as follows:

Detect layers in rocks containing oil deposits.
Can also determine the level of depth at sea ie on a ship's wall which is precisely at the bottom of the ship can be installed an oscillator or vibration source device and near the vibration source is also installed a device that can receive vibrations or hydrophones.
Can conduct geophysical surveys such as determining a location, detecting and classifying disturbances that occur on earth or referred to by being able to inform structures on earth.
And also the principle of ultrasonic reflection can be used to regulate the thickness level of the metal plate and can also detect cracks that occur in metal structures.
Thus the discussion about the "Physics Material" Definition of intensity & (Formulas - Sound Intensity Level - Application of Sound Waves) hopefully with this review can add insight and knowledge of you all, thank you very much for your visit.

Oscillators Producing Electromagnetic Waves

Oscillators Producing Electromagnetic Waves Diagnosis Using X-rays
Broken bones, internal diseases can be detected and diagnosed by doctors accurately with the help of X-rays or X-rays.
Since the discovery of X-rays in 1895 by Wilhelm Conrad Röntgen, the medical world has made rapid progress to treat internal diseases or broken bones. With the results of the X-ray film images the team of doctors got clear information which parts had to get treatment.

Radio telescope
Radio telescope to capture radio waves and detect other signals (pulsars) from outer space. The discovery of radio waves that came from outer space and was successfully detected on earth by Karl Jansky an electrical engineer from the Bell Telephone laboratory in 1931, had succeeded in developing radio astronomy. A total of 27 radio telescopes were built near Socorro in New Mexico.
For decades radio astronomy has progressed rapidly and managed to provide a picture of the universe with many detected spectrum of other waves coming from outer space such as infa red, ultraviolet, X-rays, gamma rays, and other pulsars until the discovery of neutron stars. Furthermore, it even managed to uncover many things about cosmic rays which were finally examined in depth by core physics scientists especially elementary particles.

A collection of 27 radio telescopes near Socorro
Utilization of Solar Cells To Capture Solar Energy
Solar cell
Electromagnetic waves from the sun in the form of visible light during the day can be captured by solar cells made of semiconductor materials such as silicon. Solar cells will convert this heat energy into electrical energy and can produce electrical voltage.
During the day the electricity voltage is stored in batteries or accumulators so that at night it can be used to turn on electrical equipment or heat water. Solar cells are also developed to drive cars without oil and gas.

Oscillators Producing Electromagnetic Waves
Electromagnetic waves are known to exist. The problem is can electromagnetic waves be produced continuously. Based on Ampere's law and Faraday's law, it was discovered that an electric oscillation circuit can produce continuous electromagnetic waves. The frequency produced by electromagnetic waves is called the resonance frequency, for the LC circuit to be formulated

Oscillation circuit
This principle is used in broadcasting technology both TV waves, radar waves, microwaves, and radio waves. Figure 21 shows a series of transmitters of electromagnetic waves. On the other hand the emitted electromagnetic waves can be captured through the electromagnetic wave receiver circuit

Problems example
Electromagnetic waves in a medium have a speed of 2.8 x 108 m / s. If the permittivity of the medium is 12.76 x 10-7 wb / Am, determine the permeability of the medium.

Answer:
Known:
c = 2.8 x 108 m / s,
ε = 12.76 x 10-7 wb / Am.
Using Maxwell's Equation, we get:

Settlement
That's a review of Electromagnetic Waves: Understanding, Nature, Kinds, and Formulas With Examples of Complete Problems Hopefully what is discussed above is useful. That is all and thank you.

Applications and Benefits of Electromagnetic

Applications and Benefits of Electromagnetic
Infrared
Health conditions can be diagnosed by investigating infrared rays from the body. Special infrared photographs called thermograms are used to detect blood circulation problems, arthritis and cancer. Infrared radiation can also be used in burglar alarms. A thief without his knowledge will block the beam and hide the alarm. The remote control communicates with the TV via infrared radiation produced by the LED (Light Emiting Diode) contained in the unit, so that we can turn on the TV remotely by using the remote control.

Ultraviolet
UV rays are needed in plant assimilation and can kill germs of skin diseases.

X-ray
X-rays are commonly used in medicine to photograph the position of bones in the body, especially to determine broken bones. However, the use of X-rays must be careful because the network of human cells can be damaged by using X-rays for too long.
From the discussion above, it can be concluded that the role of electromagnetic waves is very beneficial in our daily lives, without our being aware of its existence.
Electromagnetic spectrum is the range of all possible electromagnetic radiation. Electromagnetic spectrum can be explained in wavelength, frequency, or power per photon. This spectrum is directly related:
Wavelength multiplied by frequency is the speed of light: 300 Mm / s, which is 300 MmHz
The energy of a photon is 4.1 feV per Hz, which is 4.1µeV / GHz
Wavelength multiplied by energy per photon is 1.24 µeVm

Electromagnetic spectrum can be divided into several areas that range from high-energy shortwave gamma rays to microwaves and radio waves with very long wavelengths. This division is actually not very firm and grows from practical uses that have historically come from a variety of detection methods.
Usually in describing the energy of the electromagnetic spectrum expressed in electronvolts for high-energy photons (above 100 eV), in wavelengths for medium energy, and in frequencies for low energy (? = 0.5 mm). The term "optical spectrum" is still widely used in referring to the electromagnetic spectrum, even though it actually only covers a portion of the wavelength range (320 - 700 nm) [1].

Applications and benefits of electromagnetic waves in everyday life
Some examples of applications of electromagnetic waves in everyday life are described as follows:
Infrared Satellite Telescope
A Space Infrared Telescope Facility (SIRTF) infrared telescope. SIRTF is a fourth star surveillance system launched by NASA. Previously the United States space agency had launched the Hubble Space Telescope, orbited by the space shuttle in 1990; Gamma Ray Observatory, launched in 1991; and the Chandra X-Ray Observatory was launched in 1999.

Hubble Space Telescope
Each of these monitoring systems is used to observe lights of a different color, which cannot be seen from the surface of the Earth. Each system also has different functions from one another.
With the Hubble Telescope, the researchers searched for the "reddest" object, which meant it was very far away. With SIRTF will be able to see the population of stars in very distant objects because SIRTF will work in infrared light waves.
Before that in 1983 a collaboration between the United States, the Netherlands and the United Kingdom had launched IRAS (the Infrared Astronomical Satellite), which also still functions today.

Example of a Microwave Image

Example of a Microwave Image
Infrared ray
Infrared rays cover the frequency area of 1011Hz to 1014 Hz or the wavelength region of 10-4 cm to 10-1 cm. if you examine the spectrum produced by an incandescent lamp with a detector connected to a milliampermeter, the ampermeter needle is slightly above the end of the red spectrum. Rays that are not seen but can be detected above the red spectrum are called infrared radiation.
Infrared light is produced by electrons in molecules that vibrate because the object is fanned. So every hot object must emit infrared light. The amount of infrared light emitted depends on the temperature and color of the object.
Example infrared image

Visible Light / Light
Visible light or light is light that can help our eyesight. The difference in sensation in the eye due to different light frequencies or wavelengths will cause different colors. The color spectrum of light based on the sequence of rising wavelengths is:
Purple (390nm-455nm)
Blue (455nm-492nm)
Green (492nm-577nm)
Yellow (577nm-597nm)
Orange (597nm-622nm)
Red (622nm-780nm)
Examples of visible light images

Ultraviolet light
Ultraviolet light has frequencies in the area of 1015 Hz to 1016 Hz or in the wave length region of 10-8 m 10-7 m. these waves are produced by atoms and molecules in an electric flame. The sun is the main source that emits ultraviolet light on the surface of the earth, the ozone layer in the upper layer of the atmosphere is what functions to absorb ultraviolet rays and continue ultraviolet rays that do not endanger the life of living things on earth.

Example Image of Ultraviolet Light
X-ray
X-rays have frequencies between 10 Hz and 10 Hz. the wavelength is very short, which is 10 cm to 10 cm. although like that but X-rays have a strong penetrating power, can penetrate thick books, a few centimeters thick wood and 1 cm thick aluminum plate.

Example of an X-ray Image
Gamma rays
Gamma rays have frequencies between 10 Hz to 10 Hz or wavelengths between 10 cm to 10 cm. The greatest penetrating power, which causes serious effects if absorbed by body tissue.

Example Image of Gamma Rays
Application of electromagnetic waves in everyday life:
Radio
Radio energy is the lowest form of electromagnetic energy, with wavelengths ranging from thousands of kilometers to less than one meter. The most widely used is communication, for researching space and radar systems. Radar is useful for studying weather patterns, storms, making 3D maps of the earth's surface, measuring rainfall, movement of ice in polar regions and monitoring the environment. Radar wavelengths range from 0.8 - 100 cm.

Microwave
The wavelength of microwave radiation ranges from 0.3 - 300 cm. Its use is mainly in the field of communication and information transmission through open spaces, cooking, and active PJ systems. In an active PJ system, a microwave pulse is fired at a target and its reflection is measured to study the characteristics of the target. An example application is the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), which measures microwave radiation emitted from the electromagnetic spectrum of Earth's electromagnetic energy to measure evaporation, water content in clouds and rain intensity.

Schematic Diagram of Hertz Experiments

Schematic Diagram of Hertz Experiments
HERTZ'S TRIAL ABOUT ELECTROMAGNETIC WAVES
Heinrich Hertz was the first to test Maxwell's hypothesis about electromagnetic waves. Hertz's experiments have proven the truth of Maxwell's hypothesis. Then finally his name was set as a unit of frequency in SI namely HERTZ (Hz).

Schematic diagram of Hertz experiments
Through this experiment Hertz managed to generate electromagnetic waves and was detected by the recipient. This experiment succeeded in proving that electromagnetic waves which initially only form the theoretical formulation of Maxwell, actually exist at the same time confirm Maxwell's theory of electromagnetic waves.

Properties of electromagnetic waves:
Electromagnetic waves can propagate in space without a medium (Vacuum)
Is a transverse wave
It has no electric charge so it moves straight in a magnetic or electric field
Can experience reflection (reflection), refraction (refraction), integration (interference), flexing (diffraction), polarization
Changes in the electric and magnetic fields occur simultaneously, so that the electric and magnetic fields are in phase and directly proportional


ELECTROMAGNETIC WAVE SPECTRUM
The product of wavelength (l) with wave frequency (f) is equal to fast wave propagation (c). Formulated as follows.
The arrangement of all electromagnetic wave forms based on their wavelength and frequency is called the electromagnetic spectrum. The electromagnetic spectrum image below is arranged in wavelength (measured in _m units) covering a very low energy range, with high wavelengths and low frequencies, such as radio waves to very high energy, with low wavelengths and high frequencies such as X radiation -ray and Gamma Ray.
Relationship Frequency (f), Wavelength (), and electromagnetic wave propagation fast (c):

Frequency Relationship
Examples of electromagnetic spectrum:
Radio Wave
The radio waves are classified according to wavelength or frequency. If the wavelength is high, then the frequency must be low or vice versa. Radio wave frequencies start from 30 kHz and up and are grouped according to their frequency widths. Radio waves are produced by electrical charges which are accelerated through the lead wires. These charges are generated by a series of electronics called oscillators.
These radio waves are transmitted from the antenna and received by the antenna as well. You cannot hear the radio directly, but the radio receiver will first convert the wave energy to sound energy.

Micro wave
Microwaves (microwaves) are radio waves with the highest frequency above 3 GHz. If microwaves are absorbed by an object, a heating effect will appear on the object. If food absorbs microwave radiation, it gets hot in a very short interval of time. This process is used in a microwave oven to cook food quickly and economically.
Microwaves are also used on RADAR (Radio Detection and Ranging) aircraft. RADAR means finding and tracing an object using microwaves. Radar aircraft utilize the nature of microwave reflection. Because the electromagnetic wave velocity is fast c = 3 X 108 m / s, then by observing the time interval between transmission and reception.
The radar antenna can rotate in all directions which can function as a transmitter and transmitter of electromagnetic waves. If the time interval between sending the pulse to the target and receiving the reflected pulse from the target is t, then the distance of the target to the center s can be determined by the formula.