SOUND, TYPES OF SOUND, INTERFERENCE OF SOUND, CALCULATION OF VELOCITY OF SOUND IN AIR, NEWTON'S FORMULA, LAPLACE'S FORMULA, DOPPLER EFFECT, ECHO, RESONANCE, MAGNETO STRICTION & PIEZO ELECTRIC PRODUCTION OF SOUND, APPLICATION OF SOUND
A wave is a repeating disturbance that transfers energy through matter or space. There are two main types of waves - longitudinal waves, where the matter moves parallel to the direction of the wave, and transverse waves, where energy is transferred without transferring matter. Sound is a form of energy caused by vibrations that transfers through longitudinal waves. Key properties of waves include wavelength, frequency, amplitude, and speed. Sound waves can interfere constructively or destructively and be reflected, refracted, or absorbed.
Sound is a vibration that propagates through compressible media such as air or water as mechanical waves of pressure and displacement. It can be audible or inaudible. Frequency is the number of occurrences of a repeating event per unit time and is an important parameter used to specify the rate of oscillatory phenomena including sound signals. The human ear receives sound waves, and the wavelength is the spatial period of a wave - the distance over which its shape repeats. Sound travels through various media as longitudinal or transverse waves and can be studied through the fields of acoustics, which deals with mechanical waves in gases, liquids and solids, and sonar, which uses sound waves to navigate or detect objects underwater.
1) Alternating current (AC) refers to sinusoidal voltage and current waveforms. AC can be generated from sources like AC generators, wind turbines, hydroelectric power plants, and solar panels.
2) Key characteristics of AC waveforms include instantaneous value, peak amplitude, peak value, peak-to-peak value, period, frequency, phase, and whether they are periodic.
3) Sinusoidal waves can be expressed as v = Vm sin(ωt+θ), where Vm is the peak amplitude, ω is the angular frequency, t is time, and θ is the phase. The phase relationship between two sinusoidal waves indicates whether one leads or lags the other.
Inductance refers to the ability of a coil to store energy in a magnetic field. It is measured in henries. Inductors are designed to have a specific inductance and are classified by their core material as magnetic or nonmagnetic. The time constant formula, which represents the time required to establish or collapse an inductor's magnetic field, is t = L/R, where t is time in seconds, L is inductance in henries, and R is resistance in ohms.
Sound waves are longitudinal mechanical waves that require a medium such as air or water to propagate. There are two types of mechanical waves: longitudinal waves where particles of the medium move parallel to the wave direction, and transverse waves where particles move perpendicular. Interference occurs when sound waves from different sources meet and combine to produce a new wave. Constructive interference amplifies the waves while destructive interference cancels them out. Infrasonic waves have frequencies below 20 Hz and ultrasonic waves are above 20,000 Hz, the normal human hearing range. Both have applications like monitoring earthquakes and welding.
The document discusses various topics related to wave optics and the physics of light, including:
- The wave nature of light and how it explains phenomena like reflection, refraction, the formation of shadows and spectra.
- Huygens' principle which states that each point on a wavefront is the source of secondary wavelets and the new wavefront is the tangent to these wavelets.
- The laws of reflection which state that the angle of incidence equals the angle of reflection.
- Refraction and how the speed and wavelength of light changes when passing from one medium to another.
- Interference and coherence - the addition of waves to form a resultant wave, and how coherent sources are required
This document discusses resistance in electrical circuits. It begins by defining resistance as anything that resists or opposes the flow of electric current. It then states Ohm's Law, which establishes the direct relationship between voltage, current, and resistance in a circuit. The document explains how resistance is measured in Ohms and discusses factors that affect resistance such as material, cross-sectional area, length, and temperature. Graphs and examples are provided to illustrate these concepts.
A wave is a repeating disturbance that transfers energy through matter or space. There are two main types of waves - longitudinal waves, where the matter moves parallel to the direction of the wave, and transverse waves, where energy is transferred without transferring matter. Sound is a form of energy caused by vibrations that transfers through longitudinal waves. Key properties of waves include wavelength, frequency, amplitude, and speed. Sound waves can interfere constructively or destructively and be reflected, refracted, or absorbed.
Sound is a vibration that propagates through compressible media such as air or water as mechanical waves of pressure and displacement. It can be audible or inaudible. Frequency is the number of occurrences of a repeating event per unit time and is an important parameter used to specify the rate of oscillatory phenomena including sound signals. The human ear receives sound waves, and the wavelength is the spatial period of a wave - the distance over which its shape repeats. Sound travels through various media as longitudinal or transverse waves and can be studied through the fields of acoustics, which deals with mechanical waves in gases, liquids and solids, and sonar, which uses sound waves to navigate or detect objects underwater.
1) Alternating current (AC) refers to sinusoidal voltage and current waveforms. AC can be generated from sources like AC generators, wind turbines, hydroelectric power plants, and solar panels.
2) Key characteristics of AC waveforms include instantaneous value, peak amplitude, peak value, peak-to-peak value, period, frequency, phase, and whether they are periodic.
3) Sinusoidal waves can be expressed as v = Vm sin(ωt+θ), where Vm is the peak amplitude, ω is the angular frequency, t is time, and θ is the phase. The phase relationship between two sinusoidal waves indicates whether one leads or lags the other.
Inductance refers to the ability of a coil to store energy in a magnetic field. It is measured in henries. Inductors are designed to have a specific inductance and are classified by their core material as magnetic or nonmagnetic. The time constant formula, which represents the time required to establish or collapse an inductor's magnetic field, is t = L/R, where t is time in seconds, L is inductance in henries, and R is resistance in ohms.
Sound waves are longitudinal mechanical waves that require a medium such as air or water to propagate. There are two types of mechanical waves: longitudinal waves where particles of the medium move parallel to the wave direction, and transverse waves where particles move perpendicular. Interference occurs when sound waves from different sources meet and combine to produce a new wave. Constructive interference amplifies the waves while destructive interference cancels them out. Infrasonic waves have frequencies below 20 Hz and ultrasonic waves are above 20,000 Hz, the normal human hearing range. Both have applications like monitoring earthquakes and welding.
The document discusses various topics related to wave optics and the physics of light, including:
- The wave nature of light and how it explains phenomena like reflection, refraction, the formation of shadows and spectra.
- Huygens' principle which states that each point on a wavefront is the source of secondary wavelets and the new wavefront is the tangent to these wavelets.
- The laws of reflection which state that the angle of incidence equals the angle of reflection.
- Refraction and how the speed and wavelength of light changes when passing from one medium to another.
- Interference and coherence - the addition of waves to form a resultant wave, and how coherent sources are required
This document discusses resistance in electrical circuits. It begins by defining resistance as anything that resists or opposes the flow of electric current. It then states Ohm's Law, which establishes the direct relationship between voltage, current, and resistance in a circuit. The document explains how resistance is measured in Ohms and discusses factors that affect resistance such as material, cross-sectional area, length, and temperature. Graphs and examples are provided to illustrate these concepts.
The document discusses electron theory and static electricity. It defines key terms like matter, energy, atoms, ions, conductors, and insulators. It explains that atoms are made up of protons, neutrons, and electrons, and that static electricity occurs when electrons are transferred between materials that are rubbed together, resulting in one material gaining a positive charge and the other a negative charge. It also provides examples of static electricity like rubbing a balloon on wool to make it stick to a wall.
Introduction
Semiconductor is a solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
Examples: Silicon, Germanium, Carbon
Intrinsic & Extrinsic Semiconductor
Semiconductors are mainly classified into two categories: Intrinsic and Extrinsic. An intrinsic semiconductor material is chemically very pure and possesses poor conductivity. It has equal numbers of negative carriers (electrons) and positive carriers (holes). Where as an extrinsic semiconductor is an improved intrinsic semiconductor with a small amount of impurities added.
The Doping of Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
Pentavalent impurities
Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
Trivalent impurities
Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
N-Type Semiconductor
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor. Phosphorous may be added by diffusion of phosphine gas (PH3).
P-Type Semiconductor
The addition of trivalent impurities such as boron, aluminum or gallium to an intrinsic semiconductor creates deficiencies of valence electrons,called "holes". It is typical to use B2H6 diborane gas to diffuse boron into the silicon material.
Diodes
A device that blocks current in one direction while letting current flow in another direction is called a diode. Diodes can be used in a number of ways. For example, a device that uses batteries often contains a diode that protects the device if you insert the batteries backward. The diode simply blocks any current from leaving the battery if it is reversed -- this protects the sensitive electronics in the device.
Wavelength & frequency relationship of an electromagnetic wave.pdfSaiKalyani11
1. The wavelength of an electromagnetic wave is the distance between identical points on adjacent waveforms, measured as the distance between crests or troughs for transverse waves and compressions or rarefactions for longitudinal waves.
2. The frequency is the number of waves that pass through a given point in a unit of time, inversely related to wavelength, and velocity equals wavelength multiplied by frequency.
3. Shorter waves have higher frequencies as wavelength and frequency are inversely proportional - when wavelength decreases, frequency increases.
In an electrical circuit the impedance of a component is defined as the ratio of the voltage phasor v, across the component over the current phasor I , through the component.
Rectifiers convert alternating current (AC) to direct current (DC). There are two main types: half-wave and full-wave rectifiers. Half-wave rectifiers only conduct current during one half of the AC cycle, resulting in lower power output. Full-wave rectifiers conduct current during both halves of the cycle, doubling the output frequency and improving power output. Common full-wave rectifier circuits include the center-tap and bridge rectifier configurations using different diode arrangements.
The document discusses resistors, resistance, and circuits. It covers thermistors and how their resistance changes with temperature. Superconductors and how their resistance drops to zero below a critical temperature is explained. Series and parallel resistor circuits are analyzed. Methods for calculating total resistance, current, and power in circuits are provided along with example problems and their solutions.
Magnets have north and south poles and magnetic fields created by electron arrangement. Molecular theory explains magnetism at the atomic level, with molecular magnets aligning in materials. Electric currents create magnetic fields, demonstrated by patterns with iron filings. Electromagnets are coils that can be magnetized and demagnetized by switching current on and off. Moving coil meters like the milliammeter measure current through magnetic interactions between the coil and a permanent magnet.
The document discusses electromagnetic fields (EMF). It begins by defining EMF as a physical field produced by moving electrically charged objects that affects behavior of nearby charged objects. It notes EMF extends indefinitely through space and is one of four fundamental forces. The field combines electric fields from stationary charges and magnetic fields from moving charges. The document then provides examples of uses for electromagnets and discusses electromagnetic induction, transformers, exposure to EMF, and contrasts EMF with gravitational fields.
A capacitor is an electronic component that stores electric charge between two conductors separated by an insulator. Capacitors are used in applications like computer memory, camera flashes, and surge protectors. The amount of charge a capacitor can store is proportional to the potential difference between its plates and is known as its capacitance, measured in Farads. Common types of capacitors include parallel-plate and cylindrical capacitors.
Geometrical optics describes the laws of reflection and refraction of light. When light travels from one medium to another, it can be reflected, refracted, scattered, or absorbed at the interface. Reflection follows the law that the angle of incidence equals the angle of reflection. Refraction is described by Snell's law, which relates the sines of the angles of incidence and refraction to the refractive indices of the media. The bending of light occurs due to changes in speed as it passes between materials of different refractive indices. Prisms are used to demonstrate refraction and dispersion of light into its component wavelengths.
An MRI scan is a painless procedure that uses magnetic fields and radio waves to produce detailed images of organs and tissues. Preparation may involve changing into loose, metal-free clothing and avoiding food, drink, smoking, and medications containing caffeine for several hours prior. During the scan, the patient lies still inside the MRI machine while images are taken, which can take 15-90 minutes. After the scan, the patient can resume normal activities unless sedated, in which case they should avoid driving or drinking for 24 hours.
Myelography is an imaging examination that involves inserting a needle into the spinal canal and injecting contrast dye to visualize the spinal cord, nerve roots, and surrounding structures using fluoroscopy and x-rays. It is used to evaluate herniated discs, tumors, infections, inflammation, spinal lesions, and stenosis. Patients are prepped and positioned for the procedure, a needle is inserted to draw fluid and inject contrast dye, and x-rays are taken. Post-procedure care involves rest, monitoring for side effects, and encouraging fluids to eliminate the dye.
THERMIONIC EMISSION
Emission this is the process whereby electrons are emitted (given out) from a substance.
Electron emission this is the process of liberating electrons from the metal surface.
WAYS OF EMITTING ELECTRONS
There are four ways of emitting electrons which are:
THERMIONIC EMISSION Is the process of emitting electrons by applying heat energy. OR is the discharge of electrons from the surfaces of heated materials.
PHOTO ELECTRIC EMISSION Is the process of emitting electrons by application of light energy.
HIGH FIELD EMISSION Is the process of emitting electrons by application of electric field.
SECONDARY EMISSION Is the process of producing electron by application of highest speed field.
The document discusses electric current and related concepts. It defines current as the flow of electric charge from one place to another, measured in amperes. Current can be direct or alternating. Resistance is a property that weakens current flow and is measured in ohms. Ohm's law states current is directly proportional to voltage and inversely proportional to resistance. Kirchhoff's laws govern the analysis of electric circuits.
This presentation introduces p-type and n-type semiconductors. P-type semiconductors have more holes than electrons, making them positively charged, due to trivalent impurities that create holes. N-type semiconductors have more free electrons than holes, giving them a negative charge, because of pentavalent impurities that donate free electrons. Diodes are made by combining a p-type and n-type semiconductor, and are used in devices like rectifiers and LEDs.
The document discusses alternating current (AC) and provides details about its key characteristics:
1) AC electricity alternates direction periodically in a back-and-forth motion, unlike direct current which flows in one direction.
2) The instantaneous value of AC varies sinusoidally over time between a maximum and minimum value.
3) Common applications of AC include transmission of electricity over long distances using transformers and conversion to DC using rectifiers.
Electric current is the flow of electric charge through a conducting material. It is measured in amperes and defined as the rate of flow of positive charge from high to low electric potential. Resistance is a material property that impedes current flow and depends on resistivity, area, and length. Ohm's law states that current is directly proportional to voltage and inversely proportional to resistance. Direct current flows in one direction from positive to negative, while alternating current periodically reverses direction.
This document provides an overview of key concepts related to sound:
- Sound waves are longitudinal waves that travel through solids, liquids, and gases by transmitting compressions and rarefactions.
- The speed of sound depends on properties of the medium like temperature, density, and elastic modulus. In air at 0°C, the speed is 331 m/s.
- Sound intensity refers to the amount of sound energy passing through a unit area per second. The decibel scale is used to quantify loudness levels that correspond to different sound intensities perceived by humans.
This document provides an overview of key concepts related to sound:
- Sound waves are longitudinal waves that travel through solids, liquids, and gases by transmitting compressions and rarefactions.
- The speed of sound depends on properties of the medium like temperature, density, and elastic modulus. In air at 0°C, the speed is 331 m/s.
- Sound intensity refers to the amount of sound energy passing through a unit area per second. The decibel scale is used to quantify loudness levels that correspond to different sound intensities perceived by humans.
The document discusses electron theory and static electricity. It defines key terms like matter, energy, atoms, ions, conductors, and insulators. It explains that atoms are made up of protons, neutrons, and electrons, and that static electricity occurs when electrons are transferred between materials that are rubbed together, resulting in one material gaining a positive charge and the other a negative charge. It also provides examples of static electricity like rubbing a balloon on wool to make it stick to a wall.
Introduction
Semiconductor is a solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
Examples: Silicon, Germanium, Carbon
Intrinsic & Extrinsic Semiconductor
Semiconductors are mainly classified into two categories: Intrinsic and Extrinsic. An intrinsic semiconductor material is chemically very pure and possesses poor conductivity. It has equal numbers of negative carriers (electrons) and positive carriers (holes). Where as an extrinsic semiconductor is an improved intrinsic semiconductor with a small amount of impurities added.
The Doping of Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
Pentavalent impurities
Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
Trivalent impurities
Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
N-Type Semiconductor
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor. Phosphorous may be added by diffusion of phosphine gas (PH3).
P-Type Semiconductor
The addition of trivalent impurities such as boron, aluminum or gallium to an intrinsic semiconductor creates deficiencies of valence electrons,called "holes". It is typical to use B2H6 diborane gas to diffuse boron into the silicon material.
Diodes
A device that blocks current in one direction while letting current flow in another direction is called a diode. Diodes can be used in a number of ways. For example, a device that uses batteries often contains a diode that protects the device if you insert the batteries backward. The diode simply blocks any current from leaving the battery if it is reversed -- this protects the sensitive electronics in the device.
Wavelength & frequency relationship of an electromagnetic wave.pdfSaiKalyani11
1. The wavelength of an electromagnetic wave is the distance between identical points on adjacent waveforms, measured as the distance between crests or troughs for transverse waves and compressions or rarefactions for longitudinal waves.
2. The frequency is the number of waves that pass through a given point in a unit of time, inversely related to wavelength, and velocity equals wavelength multiplied by frequency.
3. Shorter waves have higher frequencies as wavelength and frequency are inversely proportional - when wavelength decreases, frequency increases.
In an electrical circuit the impedance of a component is defined as the ratio of the voltage phasor v, across the component over the current phasor I , through the component.
Rectifiers convert alternating current (AC) to direct current (DC). There are two main types: half-wave and full-wave rectifiers. Half-wave rectifiers only conduct current during one half of the AC cycle, resulting in lower power output. Full-wave rectifiers conduct current during both halves of the cycle, doubling the output frequency and improving power output. Common full-wave rectifier circuits include the center-tap and bridge rectifier configurations using different diode arrangements.
The document discusses resistors, resistance, and circuits. It covers thermistors and how their resistance changes with temperature. Superconductors and how their resistance drops to zero below a critical temperature is explained. Series and parallel resistor circuits are analyzed. Methods for calculating total resistance, current, and power in circuits are provided along with example problems and their solutions.
Magnets have north and south poles and magnetic fields created by electron arrangement. Molecular theory explains magnetism at the atomic level, with molecular magnets aligning in materials. Electric currents create magnetic fields, demonstrated by patterns with iron filings. Electromagnets are coils that can be magnetized and demagnetized by switching current on and off. Moving coil meters like the milliammeter measure current through magnetic interactions between the coil and a permanent magnet.
The document discusses electromagnetic fields (EMF). It begins by defining EMF as a physical field produced by moving electrically charged objects that affects behavior of nearby charged objects. It notes EMF extends indefinitely through space and is one of four fundamental forces. The field combines electric fields from stationary charges and magnetic fields from moving charges. The document then provides examples of uses for electromagnets and discusses electromagnetic induction, transformers, exposure to EMF, and contrasts EMF with gravitational fields.
A capacitor is an electronic component that stores electric charge between two conductors separated by an insulator. Capacitors are used in applications like computer memory, camera flashes, and surge protectors. The amount of charge a capacitor can store is proportional to the potential difference between its plates and is known as its capacitance, measured in Farads. Common types of capacitors include parallel-plate and cylindrical capacitors.
Geometrical optics describes the laws of reflection and refraction of light. When light travels from one medium to another, it can be reflected, refracted, scattered, or absorbed at the interface. Reflection follows the law that the angle of incidence equals the angle of reflection. Refraction is described by Snell's law, which relates the sines of the angles of incidence and refraction to the refractive indices of the media. The bending of light occurs due to changes in speed as it passes between materials of different refractive indices. Prisms are used to demonstrate refraction and dispersion of light into its component wavelengths.
An MRI scan is a painless procedure that uses magnetic fields and radio waves to produce detailed images of organs and tissues. Preparation may involve changing into loose, metal-free clothing and avoiding food, drink, smoking, and medications containing caffeine for several hours prior. During the scan, the patient lies still inside the MRI machine while images are taken, which can take 15-90 minutes. After the scan, the patient can resume normal activities unless sedated, in which case they should avoid driving or drinking for 24 hours.
Myelography is an imaging examination that involves inserting a needle into the spinal canal and injecting contrast dye to visualize the spinal cord, nerve roots, and surrounding structures using fluoroscopy and x-rays. It is used to evaluate herniated discs, tumors, infections, inflammation, spinal lesions, and stenosis. Patients are prepped and positioned for the procedure, a needle is inserted to draw fluid and inject contrast dye, and x-rays are taken. Post-procedure care involves rest, monitoring for side effects, and encouraging fluids to eliminate the dye.
THERMIONIC EMISSION
Emission this is the process whereby electrons are emitted (given out) from a substance.
Electron emission this is the process of liberating electrons from the metal surface.
WAYS OF EMITTING ELECTRONS
There are four ways of emitting electrons which are:
THERMIONIC EMISSION Is the process of emitting electrons by applying heat energy. OR is the discharge of electrons from the surfaces of heated materials.
PHOTO ELECTRIC EMISSION Is the process of emitting electrons by application of light energy.
HIGH FIELD EMISSION Is the process of emitting electrons by application of electric field.
SECONDARY EMISSION Is the process of producing electron by application of highest speed field.
The document discusses electric current and related concepts. It defines current as the flow of electric charge from one place to another, measured in amperes. Current can be direct or alternating. Resistance is a property that weakens current flow and is measured in ohms. Ohm's law states current is directly proportional to voltage and inversely proportional to resistance. Kirchhoff's laws govern the analysis of electric circuits.
This presentation introduces p-type and n-type semiconductors. P-type semiconductors have more holes than electrons, making them positively charged, due to trivalent impurities that create holes. N-type semiconductors have more free electrons than holes, giving them a negative charge, because of pentavalent impurities that donate free electrons. Diodes are made by combining a p-type and n-type semiconductor, and are used in devices like rectifiers and LEDs.
The document discusses alternating current (AC) and provides details about its key characteristics:
1) AC electricity alternates direction periodically in a back-and-forth motion, unlike direct current which flows in one direction.
2) The instantaneous value of AC varies sinusoidally over time between a maximum and minimum value.
3) Common applications of AC include transmission of electricity over long distances using transformers and conversion to DC using rectifiers.
Electric current is the flow of electric charge through a conducting material. It is measured in amperes and defined as the rate of flow of positive charge from high to low electric potential. Resistance is a material property that impedes current flow and depends on resistivity, area, and length. Ohm's law states that current is directly proportional to voltage and inversely proportional to resistance. Direct current flows in one direction from positive to negative, while alternating current periodically reverses direction.
This document provides an overview of key concepts related to sound:
- Sound waves are longitudinal waves that travel through solids, liquids, and gases by transmitting compressions and rarefactions.
- The speed of sound depends on properties of the medium like temperature, density, and elastic modulus. In air at 0°C, the speed is 331 m/s.
- Sound intensity refers to the amount of sound energy passing through a unit area per second. The decibel scale is used to quantify loudness levels that correspond to different sound intensities perceived by humans.
This document provides an overview of key concepts related to sound:
- Sound waves are longitudinal waves that travel through solids, liquids, and gases by transmitting compressions and rarefactions.
- The speed of sound depends on properties of the medium like temperature, density, and elastic modulus. In air at 0°C, the speed is 331 m/s.
- Sound intensity refers to the amount of sound energy passing through a unit area per second. The decibel scale is used to quantify loudness levels that correspond to different sound intensities perceived by humans.
Sound is a form of energy that produces hearing in our ears. It is produced by vibration and travels as a longitudinal wave through compression and rarefaction regions in a medium. The Bell jar experiment showed that sound cannot travel through a vacuum. Sound waves are characterized by their amplitude, wavelength, frequency and speed. Pitch is determined by frequency of vibration and loudness by amplitude.
Two loudspeakers connected to the same signal generator produce sound waves of the same wavelength. When a person walks in front of the loudspeakers, they hear the resultant interference effect. At some points, the sound waves arrive in phase and constructively interfere to produce louder sound. At other points, the waves arrive out of phase and destructively interfere, producing silence. The distance between bright or dark fringes on a screen is called the fringe width and can be calculated using the wavelength, distance between slits, and distance from slits to screen.
This document discusses fundamentals of acoustics, including:
- Sound consists of air molecule vibrations that propagate in longitudinal waves.
- Pitch is perceived as frequency and is measured in Hertz. The human range is 20Hz to 20kHz.
- Loudness relates to amplitude, power, and intensity of sound waves. It is measured in decibels on a logarithmic scale.
- Timbre is the quality that distinguishes different musical instrument sounds and is determined by the relative strengths of harmonic overtones above the fundamental pitch frequency.
1) The document discusses various properties of waves including reflection, refraction, diffraction, and interference.
2) Reflection of waves follows the law that the angle of incidence equals the angle of reflection. Refraction is caused by changes in wave speed between different mediums and follows Snell's law.
3) Diffraction causes waves to spread out when encountering obstacles. More diffraction occurs with narrow slits and longer wavelengths.
4) Interference occurs when two waves overlap. Constructive interference increases amplitude while destructive interference decreases amplitude. Interference patterns can be observed with ripple tanks and sound waves.
1. Sound is produced due to the vibration of objects and needs a medium like air, water or other materials to travel through.
2. As sound travels through a medium, it causes compressions and rarefactions that propagate the vibrations as a longitudinal wave.
3. The human ear detects sound waves that are converted into electrical signals in the cochlea and transmitted to the brain for interpretation. Frequencies between 20-2000 Hz can be heard by humans.
1. The document discusses waves and sound, including the nature of waves, types of waves (transverse, longitudinal), properties of waves like amplitude, wavelength, frequency, and speed.
2. It also covers the nature of sound waves, which are longitudinal waves that transfer energy through variations in pressure. The speed of sound depends on the medium and can be calculated using the material properties.
3. Sound intensity is defined in terms of power per unit area, and is perceived as loudness. Intensity levels are measured in decibels on a logarithmic scale compared to a reference value.
This document provides an overview of key concepts about sound waves including:
- Sound waves are longitudinal waves that cause fluctuations in air pressure.
- Pressure can be graphed against position or time to show variations from equilibrium.
- The speed of sound depends on properties of the medium like bulk modulus and density.
- In air, speed increases with temperature as density decreases.
- Wavefronts represent crests of high pressure spreading out from a source.
- Frequency determines pitch while amplitude determines loudness.
- The human ear detects sounds from 20-20,000 Hz and converts pressure waves to nerve signals.
it is about a chapter and learning this chapter is very important for class 8 and further standerds. it contains about sound,eye,ear, and its parts .all the best for your exams
Sound is produced by vibration and needs a medium to travel through. It propagates as longitudinal waves of alternating compressions and rarefactions. The human range of hearing is between 20 Hz to 20 kHz. Ultrasound above this range has many applications like cleaning, object detection and medical imaging. Sonar uses ultrasound to detect underwater objects by calculating the time taken for echo reception. The human ear collects sound via the outer ear and transmits it through the middle ear bones to the inner ear where it is converted to electrical signals for the brain to interpret as sound.
Sound is produced by vibration and needs a medium to travel through. It propagates as longitudinal waves of alternating compressions and rarefactions. The human range of hearing is between 20 Hz to 20 kHz. Ultrasound above this range has many applications like cleaning, object detection and medical imaging. Sonar uses ultrasound to detect underwater objects by calculating the time taken for echoes to return. The human ear collects sound via the outer ear and transmits it through the middle ear bones to the inner ear where it is converted to electrical signals for the brain to interpret as sound.
The document is a presentation on architectural acoustics submitted by Riyas MS. It discusses key topics in sound including:
- Generation of sound which occurs when an object vibrates and causes pressure waves in the air.
- Propagation of sound which moves through a medium like air or water via sound waves. The speed depends on the properties of the medium.
- Reception of sound which involves the perception of sound waves by the brain after vibration of a membrane like a drum.
- Other characteristics of sound discussed include frequency, wavelength, velocity, intensity, the inverse square law, and the decibel unit used to measure sound intensity.
1) The document is a lesson on acoustics that discusses sound fundamentals like frequency, wavelength, decibels and the human range of hearing.
2) It then covers acoustic concepts such as power, intensity, impedance and how they relate to a vibrating surface like a panel.
3) The document focuses on calculating the radiated acoustic power from a panel using Rayleigh's integral formulation and defines terms like transmission loss and radiation efficiency.
Sound is produced by vibrations that propagate as longitudinal waves through a medium. The document discusses the production, propagation, and characteristics of sound waves including frequency, wavelength, amplitude, and speed. It also describes how sound is detected by the human ear and converted to nerve signals that are interpreted as sound by the brain. Key parts of the ear and processes like reflection, echo, reverberation, and SONAR are explained.
Sound waves are produced by the vibration of material objects. A disturbance in the form of a longitudinal wave travels away from the vibrating source. High-pitched sounds are produced by sources vibrating at high frequency, while low-pitched sounds are produced by low-frequency sources Sound waves consist of traveling pulses of high-pressure zones, or compression, alternating with pulses of low-pressures zones, or rarefaction. Sound can travel through gases, liquids, and solid, but not through a vacuum.
Notes for JEE Main 2014 Physics - Wave Motion Part IEdnexa
The document provides information about wave motion and reflection of waves. It defines key terms related to waves like amplitude, wavelength, period, frequency. It describes the properties of simple harmonic progressive waves and gives their equation. It explains the concepts of superposition, interference and beats of waves. It discusses reflection of transverse and longitudinal waves at rigid and free surfaces. The document also describes Quincke's tube experiment to determine the wavelength of sound waves.
X-rays were discovered by Wilhelm Röntgen in 1895. They are produced when a solid target like copper or tungsten is bombarded with electrons with kinetic energies in the kilo electron volt range, emitting electromagnetic radiation. The common device used to produce x-rays is a Coolidge tube, which contains a cathode filament and anode target metal. When a voltage is applied, cathode rays hit the target at a 45 degree angle, producing invisible x-rays over a spectrum of wavelengths. X-rays are used in medicine for diagnostic imaging due to their ability to pass through matter and be captured on photographic plates.
8. ELECTRO MAGNETIC SPECTRUM (Biomedical Physics).pdfDR NIYATI PATEL
Maxwell predicted the existence of electromagnetic waves in 1865 through theoretical considerations, while Hertz confirmed their existence experimentally in 1888. Hertz's experiment was based on the fact that an oscillating electric charge radiates electromagnetic waves, supplying energy from its kinetic energy. The orderly distribution of electromagnetic radiations according to their wavelength or frequency is called the electromagnetic spectrum, which has a wide range of wavelengths from 10-14 m to 6 × 106 m. The spectrum includes radio waves, microwaves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays. These different types of electromagnetic waves have various uses including in communication technologies, medical treatments and diagnoses, food preservation, and more.
This document defines malaria and discusses its transmission, pathogenesis, clinical features, complications, diagnosis, and management. Malaria is caused by Plasmodium parasites transmitted via mosquito bites and characterized by periodic fevers. P. falciparum can cause potentially fatal malaria. Complications include tropical splenomegaly syndrome, nephropathy, and anemia. Diagnosis involves blood smears to identify parasites and antigen testing. Management consists of antimalarial drugs like quinine, addressing complications, and specific treatment for children and pregnant women in high-risk areas.
This document defines mental retardation as sub-average general intelligence that manifests during early development, resulting in diminished learning capacity and difficulty adjusting socially. It describes several clinical features of mental retardation including family history, home environment factors, physical anomalies, and delays in development. It also discusses intelligence quotient (IQ) tests which assess verbal and non-verbal abilities to determine a patient's mental age and classify their level of retardation. The causes of mental retardation include both prenatal factors like genetic conditions and perinatal factors like infections, while management involves counseling, education, rehabilitation, and treatment of behavioral issues.
The document discusses normal growth and development from conception through childhood. It describes the stages of growth from the ovum and embryo stages through infancy, childhood and adolescence. It outlines the factors that can affect growth and development such as genetics, hormones, nutrition, socioeconomic status and intellectual stimulation. Key growth parameters like weight, height and head circumference are provided for each stage of development. Milestones for gross motor, fine motor, social and language development are also outlined. Abnormal growth such as low birth weight, microcephaly and macrocephaly are defined and their potential causes discussed.
Tetanus is caused by a neurotoxin produced by Clostridium tetani bacteria that enters the body through wounds or burns. It causes muscle spasms by blocking motor neuron synapses in the central nervous system. Symptoms range from lockjaw to generalized painful muscle spasms. Treatment involves wound care, antibiotics, medications to control spasms, and supportive care like ventilation for severe cases. Prevention centers on immunization and proper wound management.
Measles is an acute viral respiratory illness characterized by fever, cough, conjunctivitis, and a maculopapular rash. It most commonly affects children between ages 3-5 years. The virus is highly infectious and spreads through direct contact or droplets. Clinical features include a prodromal stage with fever and Koplik's spots, followed by an exanthematous rash that begins behind the ears and spreads all over the body. Complications can include pneumonia, otitis media, and blindness. Prevention is through vaccination with the measles, mumps, and rubella (MMR) vaccine.
Chickenpox is primarily a disease of children caused by the varicella zoster virus. It is transmitted through respiratory droplets or direct contact. The infection causes a rash that starts on the back and chest and spreads to the face and limbs, going through macule, papule and vesicle stages before forming scabs. Complications can include bacterial skin infections or, rarely, pneumonia, encephalitis or congenital abnormalities in newborns. Treatment focuses on relieving symptoms like pruritus and treating secondary infections with antibiotics or antivirals. Vaccination provides effective prevention.
Diphtheria is caused by a bacterial infection of the respiratory tract or skin by Corynebacterium diphtheriae, which produces a toxin. The bacteria do not invade deeply but multiply locally, causing tissue necrosis and formation of a pseudomembrane. The toxin can also enter the bloodstream and cause neurological or heart complications. Symptoms vary depending on the site of infection but may include throat swelling, difficulty breathing, and skin lesions. Diagnosis involves culturing samples from infected sites. Treatment involves antitoxin administration, antibiotics, and supportive care such as airway management for laryngeal infections. Complications can affect the heart or nerves if not properly treated.
The document discusses immunization and vaccination. It defines key terms like vaccination, immunization, seroconversion, and seroprotection. It outlines the national immunization schedule from birth through adolescence according to both the universal immunization program and the Indian association of paediatrics. The schedule includes vaccines for diseases like tuberculosis, diphtheria, tetanus, pertussis, polio, hepatitis B, Hib, measles, mumps, rubella, and typhoid. The document also discusses the route of administration for different vaccines and possible adverse effects.
This document discusses several vitamin deficiencies including vitamins A, D, C, and B1. It provides details on the roles of these vitamins, signs and symptoms of deficiencies, diagnostic testing, and treatment approaches. Vitamin A is important for vision, growth, and reproduction. Vitamin D deficiency can cause rickets, a softening of the bones. Scurvy is caused by vitamin C deficiency and results in issues with collagen production. Beriberi is a thiamine (vitamin B1) deficiency that can impact the heart or nerves. Treatment for the deficiencies involves supplementation with the respective vitamins.
This document discusses malnutritional disorders in infants and children. It describes kwashiorkor and marasmus as the two main types of protein-energy malnutrition. Kwashiorkor mainly affects children aged 1-3 years and is characterized by edema, skin changes, fatty liver and hypoalbuminemia. Marasmus mainly affects children under 1 year of age and results in severe wasting and loss of muscle mass. The management of severe malnutrition involves immediate resuscitation, restoration of weight and nutritional rehabilitation over several weeks.
The femoral nerve originates from the lumbar plexus and innervates muscles in the anterior compartment of the thigh. Causes of femoral neuropathy include pelvic or femoral fractures, hip dislocations, spinal issues, and diabetes. Symptoms include sensory loss and weakness of the quadriceps and hip flexors. Special tests like the slump test and prone knee bending test isolate compression of the femoral nerve. Electromyography can help evaluate the severity and location of nerve damage. Treatment involves addressing the underlying cause, physical therapy, bracing, and surgery in severe cases.
This document discusses tibial neuropathy, including its anatomy, causes, signs and symptoms, investigations, types of injuries, and treatment options. The tibial nerve arises from the L4, L5, S1 and S2 nerve roots and supplies motor innervation to the gastrocnemius, soleus, and other calf and foot muscles. Common causes of tibial neuropathy include injection palsy, penetrating leg injuries, tarsal tunnel syndrome, and Morton's neuroma. Signs and symptoms involve sensory loss and weakness of the innervated muscles. Investigations may include MRI, EMG, and nerve conduction studies. Treatment involves conservative options like physical therapy or surgical procedures like nerve grafting or tendon transfers.
The obturator nerve arises from the lumbar plexus and supplies motor innervation to several adductor muscles of the thigh. It can be injured due to hip dislocation, pelvic fracture, or compression by a mass. Injury results in sensory loss in the thigh and paralysis of the adductor muscles. This causes the patient to walk with a narrow base and have loss of hip adduction range of motion. Treatment involves physiotherapy like electrical stimulation and stretching exercises to prevent deformities while the nerve regenerates over months. Special tests like Tinel's sign and slump test can help evaluate an obturator nerve injury.
The common peroneal nerve is a branch of the sciatic nerve that innervates muscles of the lower leg and foot. Common peroneal neuropathy can result from compression of the nerve due to trauma, fractures, immobilization, or other causes. This leads to weakness of ankle dorsiflexors and foot everters, sensory loss, and a foot drop gait. Diagnosis involves nerve conduction studies and EMG. Treatment may include immobilization, physical therapy, splinting, and tendon transfers in severe cases.
This document discusses sciatic neuropathy, including its anatomy, causes, signs and symptoms, investigations, types of injuries, and treatments. The sciatic nerve is the thickest nerve in the body and originates from the lumbosacral plexus, supplying muscles in the lower limb. Causes of sciatic neuropathy include pelvic fractures, hip dislocations, and compression by tumors. Signs include sensory loss and muscle paralysis below the knee, resulting in foot drop and gait abnormalities. Investigations include MRI, EMG, and nerve conduction studies. Treatments focus on preventing contractures and foot drop through electrical stimulation, splinting, and customized footwear.
Force is a push or pull that can change the motion of an object. There are three laws of motion defined by Newton:
1) An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
2) The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the direction of the net force.
3) For every action, there is an equal and opposite reaction.
Forces can be balanced or unbalanced. Balanced forces cancel each other out while unbalanced forces result in changes to motion.
This document discusses radial neuropathy, which affects the radial nerve that provides motor innervation to the triceps and multiple extensor muscles of the forearm and hand. It summarizes the anatomy, causes such as compression or injury, signs and symptoms including wrist and finger drop, investigations including electrodiagnostic studies, types of injuries, special tests, surgical management including tendon transfers, and physiotherapy approaches.
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
TEST BANK For An Introduction to Brain and Behavior, 7th Edition by Bryan Kol...rightmanforbloodline
TEST BANK For An Introduction to Brain and Behavior, 7th Edition by Bryan Kolb, Ian Q. Whishaw, Verified Chapters 1 - 16, Complete Newest Versio
TEST BANK For An Introduction to Brain and Behavior, 7th Edition by Bryan Kolb, Ian Q. Whishaw, Verified Chapters 1 - 16, Complete Newest Version
TEST BANK For An Introduction to Brain and Behavior, 7th Edition by Bryan Kolb, Ian Q. Whishaw, Verified Chapters 1 - 16, Complete Newest Version
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Kat...rightmanforbloodline
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachAyurveda ForAll
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
2. INTRODUCTION
Sound waves are longitudinal waves that can
travels through any material medium with a
speed that depends on the properties of the
medium
As sound travels through a medium, the
particles of the medium vibrant along the
direction of motion of the wave
This is in contrast to a transverse wave where
the particles motion is perpendicular to the
direction of propagation
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4. The displacement that occurs as a result of
sound waves involved the longitudinal
displacements of individual molecules from
their mean or equilibrium positions
This results in a series of high and low pressure
regions called compression and rarefaction
respectively
“Sound waves are longitudinal waves that travel
through all media in the form of compression
and rarefactions”
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6. ORIGIN OF SOUND
Sound is
A form of energy made by vibration
When an object vibrates it causes the air
particles around it to move
These particles bump into particles close to
them and this continues until they run out of
energy
Sound is a variation in the pressure of the
air of a type which has an effect on our
ears and brain
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7. TYPES OF SOUND
Sound waves are often categorised
into three group
1. Audible – Hear easily
2. Infrasonic – inaudible sound
3. Ultrasound – inaudible sound
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9. AUDIBLE AND INAUDIBLE WAVE:
Produce compression and rarefactions in
air. However no audible sounds are
produced because the frequency of such
vibrations is too low (<20 hz) to affect our
auditory nerves.
Likewise if the frequency of sound is high
(>20 khz), no sound is heard by the
human ear. It is because the vibrations
are so rapid that auditory nerves do not
respond to them
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10. 1) AUDIBLE WAVES:
Audible waves are sound waves that
human ear can hear
The range of human hearing is 20 HZ to 20
Khz. In other words, we cannot hear
waves of frequency below 20 hz or above
20 khz
The audible waves can be generated in a
variety of ways such as by musical
instruments, human vocal cords and
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11. 2) INAUDIBLE WAVES:
Those waves which human ear cannot hear are
called inaudible waves
There are two types of inaudible waves like
infrasonic and ultrasonic
Infrasonics are longitudinal waves with
frequencies below 20 hz. Earthquake waves are
an example
Ultrasonic waves are longitudinal waves with
frequencies above 20 khz. For example they can
be generated by inducing vibrations in a quartz
crystal with an applied alternating electric field.
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12. Sound may be broadly classified into two
general group:
1. Musical sound
2. Noise
The difference between a musical sound
and noise is subjective, exa- its depends
upon the sense of a person
A sound which is musical to someone may
be noise to others
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13. Musical sound
It is a pleasant, continuous and uniform sound
produced by regular and periodic vibration
E.g- sound produced by tuning fork, flute, piano
etc
In musical sound there is no sudden change in
loudness
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15. Noise
It is an unpleasant, discontinuous and non uniform
sound produced by irregular succession of
disturbances
All sounds other than musical sounds are noise
E.g- sound produced by a falling brick, clapping of
two wooden blocks etc
In noise there is sudden changes in loudness
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16. CHARACTERISTICS OF SOUND
WAVES
Sound waves are characterised by its
pitch (frequency), loudness (intensity)
and quality.
The speed of the sound depends on the
medium transmitting it
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18. 1. AMPLITUDE- it is maximum displacement
of the medium from its equilibrium state
when a mechanical wave passes through
the medium. The amplitude of wave is
denoted by “a”.. SI is “m”
2. WAVELENGTH- the distance between two
successive crest and two successive trough
is called wavelength of the wave. It is
denoted by “λ” .. SI is “m”
3. FREQUENCY – The frequency of wave is
the number of complete cycle that pass a
given point in one second. It is denoted by
“f”. Unit of frequency is Hz. 14-09-
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20. 4. TIME PERIOD: the period of a wave is the
time taken by the wave source to complete
1 vibration or cycle. It is denoted by “T”..
SI is “sec”.. 1/F
5. WAVE VELOCITY: The distance covered by
a wave in one second is called wave
velocity. It is denoted by “v” and is
measured in m/s in SI units
6. VIBRATION: any regularly repeated to
and fro motion of change is known as
vibration
7. PHASE : The stage in a cycle that a wave
has reached at a particular time from some
reference point.
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21. RELATION BETWEEN WAVE
VELOCITY, FREQUENCY &
WAVELENGTH
The velocity of a wave is v, time period T,
frequency f and wavelength λ.
By the definition of wavelength,
Wavelength = Distance travelled by the wave in
one time period, i.e., in T second.
Or wavelength = Wave velocity x Time period
Or, λ = v x T
Or, λ = v x 1/F [ T = 1/F]
Therefore, v = Fλ
Therefore, Wave velocity = Frequency x
wavelength
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22. INTERFERENCE OF SOUND
WAVES
When two or more wave of sound of same
frequency travelling in almost same direction
superimpose, the resultant intensity in the region
of superimposition is different than the intensity
of individual waves.
The modification in the distribution of intensity
of sound in the region of superposition is called
interference
Depending upon the way the waves superimpose,
the interference is of two types:
1) Constructive Interference
2) Destructive interference
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24. CONSTRUCTIVE
INTERFERENCE
When the waves superimpose in such a way that their
maxima and minima correspond with each other, the
resultant amplitude is the sum of the amplitudes due to
separate waves
As the intensity is proportional to the square of the
amplitude and hence the resultant intensity at this
point is increased
This phenomenon is called constructive interference
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25. EFFECTS
In constructive interference, two waves
of sound reinforce each other
In constructive interference, one can hear
a louder sound
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26. DESTRUCTIVE INTERFERENCE
When the waves superimpose in such a
way that the maxima of one corresponds
with the minima of other, the resultant
amplitude is equal to the difference of
the amplitude due to separate waves.
This is termed as destructive interference
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27. EFFECTS
In destructive interference, two waves
cancel the effects of each other
Due to destructive interference we can
not hear sound or the intensity of sound is
decreased
Thus, due to phenomenon of interference
we get maximum sound (due to
constructive interference) and minimum
sound (due to destructive interference)
which are called louder sound and null
sound respectively
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28. CALCULATION OF VELOCITY
OF SOUND IN AIR
NEWTON’S FORMULA:
NEWTON’S Assumed that the propagation of sound waves
in air is an isothermal phenomenon.
i.e – a process in which temperature remains constant and
boyle’s law holds good (a relation concerning the
compression and expansion of a gas at constant
temperature)
He argued that the small amount of heat which is
produced at compression is rapidly taken away to the
places of rarefaction where a slight cooling is produced
In this way the temperature of the gas remains constant
Thus for a given mass of gas at pressure P and volume V
PV= CONSTANT 14-09-
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29. According to theoretical consideration v = √E/ρ
Where E = Coefficient elasticity of medium, ρ = density
of medium
But in this we are taking air/gas as medium so
considering bulk modulation v =√B/ρ
According to newton's assumption this is isothermal
process during compression and rarefaction
temperature is not changed v = √Kiso /ρ ….. (1)
During compression pressure is increase
During rarefraction pressure is decrease
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30. If PV = CONSTANT, By differentiating, we get
P.dv + V.dP = 0 P.dv = - V.dP
P = dP / - (dv/V) = change in pressure/ Volume strain =Kiso
Substituting this value of P in the velocity expression
v = √Kiso /ρ = √P / ρ ….. (2)
This is newton’s formula.
V = √P / ρ = √76× 13.6 × 980 / 0.00129 = 280 m/s
where P= h.d.g = (height = 76 cm of hg, density = 13.6 gm -3, gravity =
980 cm/s2 )
Where ρ = 1.293 kg/m 3 = 0.00129 g/m3
The experimental value of the velocity of sound in air at
N.T.P is 332 m/s
Difference between the experimental and theoretical value
of velocity of sound in air = 332 – 280 = 52 m/s 16 %
difference between actual value
So newton’s formula is not acceptable
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31. LAPLACE’S FORMULA
Laplace pointed out that the propagation of sound
waves through air is an “ISOTHERMAL PROCESS”(As
suggested by newton’s formula) but it is an adiabatic
process
He argued that due to the reasons
1. that compression and rarefaction in sound waves take place
very rapidly
2. large distances between compression and rarefactions
3, poor conductivity of air, there is no appreciable heat flow from
regions of compressions (temp slightly high) to the regions of
rarefactions (temp slightly low)
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32. Thus the conditions do not remain isothermal (i.e
temp changes)
The relation between pressure and volume of air is
governed by the adiabatic relation,
pVγ = Constant, where γ is the adiabatic constant….
(1)
So according to laplace formula
The value of “γ” for air is 1.41 (value of adiabatic
normal ratio) substituting the value of γ, P and ρ we
get
V = √1.41 ×76× 13.6 × 980 / 0.00129 = 331.6 m/s
So this value is good in agreement with the
experimental value
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35. DEFINITION
When a source generating wave moves relative to an
observer, or when an observer moves relative to a
source, there is an apparent shift in frequency
This apparent change in frequency due to the motion of
the source (receiver) is called the Doppler effect, after
Christian Doppler (1808-1853), the Austrian physicist
who first explained this phenomenon
The Doppler effect occurs for all types of waves
whenever there is a relative motion between the source
of waves and the observer
The greater the speed of the source, the greater will be
the Doppler effect
“the apparent change in the observed frequency of a
wave due to the relative motion between the source of
waves and observer is called Doppler effect”
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37. RESTING SOUND SOURCE
The Doppler effect occurs when a source of waves moves
relative to the observer
You have certain experiences this effect with sound. You are
familiar with the rise and subsequent drop in pitch of an
automobile horn as it approaches and then passes
In other words, frequency of sound is raised when the source of
sound approaches you and lowered when the source is moving
away from you
fs = fo (where fs is source of frequency & fo is observer
frequency)
Person hearing sound observer
Emitting sound source
Acc to this 2 situations
1. when the source moves stationary observer
2. when the observer moves stationary source
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38. The relationship describing the Doppler shift for
moving source is given by
fo = v/v±vs × fs
Where
fo = apparent frequency
v = velocity of sound
vs = velocity of source of sound S
fs = frequency emitted by the source
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40. SOUND SOURCE MOVING
TOWARDS STATIONARY OBSERVER
Apparent frequency fo = v/v-vs × fs
since (v-vs) < v, fo > fs
so the apparent frequency increase when
the source of sound moves towards the
stationary observer
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41. SOUND SOURCE MOVING AWAY
FROM OBSERVER
Apparent frequency fo = v/v+vs × fs
since (v+vs) > v, fo < fs
so the apparent frequency decrease when
the source of sound moves away from the
stationary observer
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43. OBSERVER MOVE
fo = v±vo / v × fs
Where fs = frequency emitted by the source
fo = apparent frequency
v = velocity of sound in air
vo = velocity of observer O
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44. SOURCE STATIONARY AND
OBSERVER MOVING TOWARDS IT
Apparent frequency fo = v+vo / v × fs
(v+vo ) > v , fo > fs
When observer is moving towards a stationary
source of sound , the apparent frequency is
increased
An observer moving towards a stationary
source hears an increase in frequency
because he intercepts the crests more
frequently than he would if he were
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45. SOURCE STATIONARY AND
OBSERVER MOVING AWAY FROM IT
Apparent frequency fo = v-vo / v × fs
(v-vo ) < v , fo < fs
When observer is moving away from a
stationary source of sound , the apparent
frequency is decreased
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47. INTRODUCTION
Echo are sound waves that are reflected back
when the sound wave hits a flat, firm surface
In audio signal processing & acoustics an echo
(plural echos) is a reflection of sound, arriving at
the listener some time after the direct sound
Typical examples are the echo produced by the
bottom of a well, by a building or by the walls of
an enclosed room and an empty room
A true echo is a single reflection of the sound
source
It word echo derived from the greek word
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48. An echo can be explained as a wave that
has been reflected by a discontinuity in
the propagation medium and returns with
sufficient magnitude
Echoes are reflected off walls or hard
surfaces like mountains
Echoes may be desirable (as in sonar) or
undesirable (as in tele-phone system)
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49. Application of ECHO
1. To find out submarines from surface
2. in fishing boats, to find out large shoals
of fish
3. To measure the depth of the sea
4. To locate a sunken shipwreck or cargo
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50. RESONANCE & VELOCITY OF
SOUND BY RESONANCE METHOD
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51. RESONANCE – when a vibrating objects set up
air vibrations in an enclosed space, the sound
vibrations in the air very weak at some
frequencies and strong at other frequency
The frequency at which the sound vibrations
are strong are called resonant frequency of the
system and the phenomenon is known as
resonance
“The phenomenon of making a body vibrate
with its natural frequency under the influence
of another vibrating body with the same
frequency is called resonance” 14-09-
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52. When 2 waves of equal wavelength and amplitude propagating
in opposite directions superimpose on each other then
interference occurs and the resultant wave is called a standing
wave
In standing wave the particles of the medium at certain points
do not oscillate called as nodes
At certain point the particles of the medium have maximum
amplitude of oscillation called as antinode
In standing waves , the distance between
Two consecutive nodes / antinodes λ/2
A node & successive antinodes λ/4
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53. SINGLE LOOP PATTERN
In fig , there is only one antinode which is at the centre
of the string and it is called single loop pattern
Here L= λ/2
λ = 2L
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54. TWO LOOP PATTERN
This pattern has three nodes and two successive
antinodes and it is said to be a two loop pattern
Here for the left and right going waves have must have
the wavelength λ = L
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55. THREE LOOPS PATTERN
Third pattern is shown in fig
It has four nodes and three antinodes its called three
loops pattern
Here the wavelength is λ = 2/3 × L
So continues in this way wavelength is λ = 2/n × L
Where n = 1,2,3,4….
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56. Resonance frequency
The resonance frequencies that corresponds to these
wavelength are given by, f = v/λ
Where λ = 2/n × L
So f = nv / 2L (where n =1,2,3…..)
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58. INTRODUCTION
The word ultrasonic combined the latin roots
ultra beyond + sonic sound
Ultrasonic waves refers to sound waves
produced by an object vibrating at a frequency
higher than the human ear can hear (above 20
khz)
By using modern techniques it has become
possible to produce ultrasonic waves of
frequency upto 25 billion Hz has wavelength
of 10 -8 m, comparable with x ray wavelength
An ultrasonic wave is highly energetic and has
extremely short wavelength becoz of its high
frequency & energy
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59. The use of ultrasonics, especially in the
field of medicine & in various industries is
because of its small wavelength & high
energy
The field of ultrasonics have applications
for imaging, detection and navigation
Sound waves having frequency less than
the audible range (< 20 hz) are called
infrasonic
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60. PROPERTIES OF ULTRASONIC
WAVES
1. They are likely energetic
2. Just like ordinary sound waves, us waves get
reflected, refracted & absorbed
3. Their speed of propagation depends upon their
frequency
4. US show very negligible diffraction due to their
small wavelength . hence they can travel over long
distances without any loss of energy
5. The liquid through which US wave pass, behaves as a
diffracting grating under monochromatic light
6. They produce intense heating effect when passed
through a substance
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61. ULTRASONIC PRODUCTION
US waves cannot be produced by the usual methods, like
from a diaphragm of loudspeaker fed to alternating
current
This is due to the fact that at very high frequency the
inductive effect of loudspeaker coil is so large that
practically no current passes through it
Moreover, the diaphragm of a loudspeaker cannot vibrate
at such high frequencies
Therefore, different methods are specially used for the
production of US wave
US Waves are produced by the 2 methods
1. Magneto striction generator / oscillator 100 kHz
2. Piezo electric generator/ oscillator above 100 kHz
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62. MAGNETO-STRICTION
GENERATOR
Based on the phenomenon of “magneto striction
effect”
Principle- Magnetostriction effect
When a ferromagnetic rod like iron / nickel is
placed in a magnetic field parallel to its length,
the rod experiences a small change in its length
called magnetostriction effect
The change in length (increase/decrease) produced
in the rod depends upon the magnitude of the
magnetic field, the materials and is independent
of the direction of the magnetic field applied
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64. If the rod is placed inside a coil carrying an alternating
current , then it suffers the same change in length for
each half cycle of alternating current
This result in setting up vibrations in the rod whose
frequency is twice that of alternating current
Ordinarily the amplitude of the vibrations of rod is small
the frequency of the alternating current is the same
as the natural frequency of the rod, then resonance
occurs and the amplitude of vibration is considerably
increased
Sound waves are now emitted from the end of the rod
Moreover if the applied frequency is of the US frequency,
the rod sends out US waves
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66. A ferromagnetic rod AB made up of Ni is clamped in middle
c as shown
Coil of wires L , L1 are winded at the ends of A & B
One end of the coil L1 is connected to the base of an NPN
transistor and the other end of coil L is connected to the
emitted and the negative terminal of a battery
A variable capacitor C1 is connected across the coil L
One end of the variable capacitor is connected to the
collector circuit, whereas the other end of the variable
capacitor is connected to the positive end of the battery
through a mA
The natural frequency of the rod is given by n =
P/2L√E/D….. (1)
Where L is the length of the rod, E is young’s modulation,
D is the density of the rod materials and P is the harmonic
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67. WORKING
When battery is switched on, the circuit L C sets up
alternating current of frequency f = 1/2∏√LC in
collector circuit
This alternating current flows through coil L1 , it causes
a corresponding change in the magnetisation of the rod,
which causes a change in the length of the Ni rod
This change in the length of the rod produces an e.m.f
in coil L1
This e.m.f is applied to the base of transistor
This change of e.m.f. produced an amplified current
change in the circuit
In the coil L which again cause a change of length of Ni
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68. In this way oscillation of rod is maintained. The
oscillation frequency f of the Ni rod is controlled by
the variable capacitor C and is given by f = 1/2∏√LC
….. (2)
If this frequency matches with the natural
frequency of the rod, resonance will occurs
By adjusting the length of the rod and the capacity
of the condenser, high frequency oscillations of
different frequencies are obtained
Now the rod vibrates longitudinally with maximum
amplitude and generates ultrasonic wave of high
frequency from its ends
Frequency can be extended upto 3×105 Hz
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69. ADVANTAGES
1. The design of this oscillator is very simple & its
production – low cost
2. At low US frequencies, the large power output can be
produced without the risk of damage of the oscillatory
circuit
DISADVANTAGES
1. It has low upper frequency limit & cannot generate
US frequency above 300 khz
2.The frequency of oscillations depends on temperature
3.There will be losses of energy due to eddy current
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70. PIEZO ELECTRIC GENERATOR/
OSCILLATOR
Based on the phenomenon of “Piezo electric effect”
Principle- Piezo electric effect
Transducer device that converts one form of
energy into another form
When certain crystals like quartz & tourmaline etc. ,
are stretched or compressed along certain axis (k/a
mechanical axis), an electrical potential difference
is produced along a perpendicular axis (k/a electric
axis)
The converse of Piezo electric effect is also true
pressure energy converts into electric energy
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73. When alternating potential difference is applied
along the electric axis, the crystal is set into
elastic vibration along the corresponding
mechanical axis
This is k/a “INVERSE PIEZO ELCTRIC EFFECT OR
ELECTROSTRICTION”
If the frequency of electric oscillations
coincides with the natural frequency of the
crystal, the vibrations will be of large
amplitude
This phenomenon is utilized for the production
of US waves
Transducer device that converts one form of
energy into another form
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75. The experimental arrangement is shown in figure
The high frequency alternating voltage which is applied to
crystal is obtained by Hartley oscillatory circuit
The Hartley circuit consist of tuned oscillatory circuit
One end of the tuned circuit is connected to the base of
transistor while the other is connected to the emitter
The coil L1 & L2 of the oscillator circuit are taken from the
primary of transformer
Inductor & capacitor are connected parallel
The crystal plate is sandwiched between metallic foils (AB)
and forms a parallel plate capacitor This is coupled to
the electronic oscillator through primary coil L3 of the
transformer T
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76. WORKING
When battery is switched on by pressing switch S
the oscillator produces high frequency
oscillations with frequency f = 1/2∏√L1C1
The frequency of this oscillations can be varied
with the help of variable capacitor C1
The e.m.f developed in oscillatory circuit
induces an e.m.f. in coil L3 due to transformer
action
As a result, the crystal is now under high
frequency alternating voltage
Inverse Piezo electric effect takes place and the
crystal contracts and expands alternatively. The
crystal is set into mechanical vibrations
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77. The frequency of the vibration is given by n = P/2l √E/D
Where P= 1,2,3… etc. for fundamental, first harmonic ,
second harmonic etc
E = young’s modulus of crystal
D= density of the crystal
The capacitor C1 is varied till the frequency of
oscillation matches with the natural frequency of
vibration of the crystal. Under this condition the crystal
generates high power US waves
The vibrating crystal produces longitudinal US waves of
large amplitude
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78. ADVANTAGES
It is more efficient than magnetostriction oscillator
US Frequencies as high as 5×108 Hz or 500 MHz can be
obtained with this arrangement
The output of this oscillator is very high
It is not affected by temperature & humidity
DISADVANTAGES
The cost of Piezo electric quartz is very high
The cutting & shaping of quartz crystal are very
complex
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79. APPLICATION
US have found numerous applications in the
following field
1. Communication
2. Industry
3. Scientific world
4. Medical world
They are so useful mainly due to the following
reasons
1. At sufficiently high frequency almost parallel beam
of plan waves can be propagated
2. As the wavelengths are small, measurements can
be made on a small sample without affecting the
physical conditions like temperature, density etc
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80. 1. depth of the sea
Know that US waves are highly energetic & shows a little
diffraction effect.
Thus they can be used for finding the depth of the sea
2. cleaning & clearing
The waves can be used for cleaning utensils, washing
clothes, removing dust
3. direction signalling
US wave can be concentrated into a sharp beam due to
smaller wavelength and hence can be used for signalling
from ship to ship specially in submerged submarines
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81. 4. Metal cutting
Us wave can be used for drilling and cutting process in
metals
5. Coagulation & crystallisation
The particles of a suspended liquid can be brought quite
close to each other using US so that coagulation may
take place which helps in the rate of crystallisation
6. Disease treatment
The body part s affected due to neuralgia or rheumatic
pain US get great relief
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