Wave motion and its applicationsWave motion, propagation of disturbance

That is deviations from a state of rest or equilibrium Wave motion is a form of disturbance produced in the medium by the repeated periodic motion of the particles of the medium.

Transverse Waves:

 Displacement of the medium is perpendicular to the direction of propagation of the wave.

Wave length

A wavelength is a measure of distance between two identical crests (high points ) or between two identical troughs ( low points ) in a wave. Wavelengths represent a repeating pattern of traveling energy, such as light or sound.

Time Period

A time period  is the time needed for one complete cycle of vibration to pass in a given point.

Frequency

As the frequency of a wave increases, the time period of the wave decreases. The unit for time period is hertz

OR

Frequency is the number of occurrences of a repeating event per unit of time the number of waves that pass a fixed point in a given amount of time ( unit time )The SI unit for wave frequency is the hertz (Hz)

Amplitude

Amplitude the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position.

Relation between velocity, wave length, frequency

Time Period (T) It is defined as the time taken to complete

oscillation

f = 1 / T--------- (i)

The wave speed (v) is defined as the distance traveled by a wave per unit time. If considered that the wave travels a distance of one wavelength in one period,

ν=λ/T ----------- (ii)

As we know that T = 1/f ----------- (iii)

hence we can express the above equation as,

V = f λ

The wave speed is equal to the product of its frequency and wavelength, and this implies the relationship between frequency and wavelength.

SHM

 Simple harmonic motion is a special type of periodic motion OR oscillation motion where the restoring force is directly proportional to the displacement and acts in the direction opposite to that of displacement.

Cantilever

Cantilever a long projecting beam or girder fixed at only one end, used in bridge construction.

Types of vibration 

1. free vibration

2. forced vibration

3. damped vibration

1 . free vibration

Free vibration occurs when a mechanical system is set in motion with an initial input and allowed to vibrate freely.

Examples of this type of vibration are pulling a child back on a swing and letting it go, or hitting a tuning fork and letting it ring..

2. Force vibration

Forced vibration is when a time-varying disturbance (load, displacement or velocity) is applied to a mechanical system.

3. Damped vibration

The disturbance can be a periodic and steady-state input

Examples include a washing machine shaking due to an imbalance, vibration of a building during an earthquake. Damped vibration: When the energy of a vibrating system is gradually dissipated by friction and other resistances, the vibrations are said to be damped.

Echo

Echo is a reflection of sound that arrives at the listener with a delay after the direct sound. The delay is directly proportional to the distance of the reflecting surface from the source and the listener. 

Noise

Noise is unwanted sound judged to be unpleasant, loud or disruptive to hearing

Co-efficient of absorption

The absorption coefficient is a representative term for determining how far incident light of a certain wave length penetrates a material before being absorbed.

Ultra sonic wave

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz in healthy young adults. 

SONAR, RADAR

Sonar (originally an acronym for sound navigation ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.

Sonograms (i.e. baby pictures) Non-destructive examination (checking for internal cracks or voids) Sonar (underwater detection of obstacles) Welding (plastics or metals) Cleaning (often jewelry) Cutting / Slicing (fabrics, plastic films) De-gating, staking, swaging, inserting (random plastic manufacturing processes) Surgery (to make incisions) Machining Additive Manufacturing Wire / tube drawing Rock breaking Proposed, possible, but not quite totally proven: Keeping windshield clean Repelling pests Cleaning algae from ponds

Optics Reflection:-

Reflection is the change in direction of a wave front at an interface between two different media so that the wave front returns into the medium from which it originated. Common

Examples

Include the reflection of light, sound and water waves.

Refraction:-

In physics refraction is the change in direction of a wave passing from one medium toanother or from a gradual change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience

refraction.

Law of refrection:-

Snell's law is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air. Law of reflection:- The law of reflection states that the incident ray, the reflected ray, and the normal to the surface of the mirror all lie in the same plane. Furthermore, the angle of reflection is equal to the angle of incidence . ... This type of reflection is called diffuse reflection, and is what

Law of reflection:-

The law of reflection states that the incident ray, the reflected ray, and the normal to the surface of the mirror all lie in the same plane. Furthermore, the angle of reflection is equal to the angle of incidence . ... This type of reflection is called diffuse reflection, and is what enables us to see non-shiny objects.

Power of lens:-

The diopter is the unit of measure for the refractive power of a lens. The power of a lens is defined as the reciprocal of its focal length in meters, or D = 1/f, where D is the power in dypoters and f is the focal length in meters. Lens surface power can be found with the index of refraction and radius of curvature.

Lens formula:-

The lens formula is applicable both in convex lenses and concave lenses. The lens formula is applicable both in convex lenses and concave lenses. ... The focal length of a lens in air can be calculated from the lens maker's equation: The focal length f is positive for converging lenses and negative for diverging lenses.

Total internal reflection:-

The complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.

Microscope and its use:-

A microscope is an instrument used to see objects that are too small to beseen . One of the latest discoveries made abo+ ut using an electron microscope is the ability to identify a virus ...

Uses: Small sample observation

Related items: Optical microscope Electron microscope

Telescope and its use:-

An optical telescope which uses lenses is known as are refracting telescope or a refractor; one which uses a mirror is known as a reflecting telescope or reflector. Besides optical telescopes, astronomers also use telescopes that focus radio waves, X-rays, and other forms of electromagnetic radiation.

Electrostatics

Unit charge:-

Charge is one electrostatic unit, esu, or statcoulomb. In the metre–kilogram–second and the SI systems, the unit of force (newton),the unit of charge (coulomb), and the unit of distance (metre ) are all defined independently of Coulombs so the proportionality factor k is constrained to take a value consist.

Unit of charge:-

Coulomb is the standard unit of charge. One Coulomb of charge is equal to electrons or protons.

Coulomb Law

 Coulomb's law states that: The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

Electric field:-

A region around a charged particle or object within which a force would be exerted on other charged particles or objects.

Electric flow density:-

In electromagnetism, current density is the electric current per unit area of cross section. The current density vector is defined as a vector whose magnitude is thee electric current per cross-sectional area at a given point in space, its direction being that of the motion of the charges at this point.

Electric field density:-

. They are operationally defined differently: The electric field intensity is defined as the force on a unit test charge and given by the units V/m. The displacement field (electric flux density) is defined by charge density built up on a test capacitor and given in units of Coulombs per square meter.

Current Electricity Electric current

Electric current is defined as the rate of flow of negative charges of the conductor. In other words, the continuous flow of electrons in an electric circuit is called an electric current

Direct and alternative current

Alternating Current (AC) is a type of electrical current, in which the direction of the flow of electrons switches back and forth at regular intervals or cycles. Direct current (DC) is the unidirectional flow of electric charge. A battery is a good example of a DC power supply.

Resistance, Specific Resistance and conductor

Specific resistance of a conductor is the resistance of a conductor of unit length and unit area of cross section. ... Specific resistance or resistivity is the resistance per unit length and area of cross section of a conductor .It is a property of a material.

Series and parallel combination of resistance

Series.

The current is the same through each resistor. The total resistance of the circuit is found by simply adding up the resistance values of the individual resistors: equivalent resistance of resistors in series: R = R1 + R2 + R3 + ... A series circuit is shown in the diagram above.

Parallel,

Voltage is the same across each component of the parallel circuit. The sum of the currents through each path is equal to the total current that flows from the source. You can find total resistance in a Parallel circuit with the following formula: 1/Rt = 1/R1 + 1/R2 + 1/R3 +...

Ohm’s law.

Ohm's law states that the current through a conductor between two points is directlyproportional to the voltage across the two points. ... More specifically, Ohm's law .

V =IR

I =V/R

R =V/I

Electric power

Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries.

Krichoff’s Law with Example

Electromagnetism Magnetic field

The magnetic field is defined from the Lorentz Force Law, and specifically from the magnetic force on a moving charge:

The magnitude of the force is F = qvsinθ where θ is the angle < 180 degrees between the velocity and the magnetic field. This implies that the magnetic force on a stationary charge or a charge moving parallel to the magnetic field is zero.

Magnetic flux

In physics, specifically electromagnetism, the magnetic flux (often denoted Φ or ΦB) through a surface is the surface integral of the normal component of the magnetic field passing through that surface. The SI unit of magnetic flux is the weber (WB).

Faraday’s Law

States that the absolute value or magnitude of the circulation of the electric field E around a closed loop is equal to the rate of change of the magnetic flux through the area enclosed by the loop. The equation below expresses Faraday's law in mathematical form.

Electro magnetic Induction

Electromagnetic induction is the production of voltage or electromotive force due to a change in the magnetic field. Electromagnetic induction was discovered by Michael Faraday in the 1830s.Many electrical components and types of equipment work based on the principle of electromagnetic induction.

Type of magnetic substance

Three types of magnetic substance

1. Diamagnetism2. Paramagnetic

3. ferromagnetism

DiamagnetismA diamagnetic substance is one whose atoms have no permanent magnetic dipole moment. When an external magnetic field is applied to a diamagnetic substance such as bismuth or silver a weak magnetic dipole moment is induced in the direction opposite the applied field. All materials are actually diamagnetic, in that a weak repulsive force is generated by in a magnetic field by the current of the orbiting .

Paramagnetic-:Para magnetism is a form of magnetism where by certain materialsare weakly attracted by an externally applied magnetic field, and forminternal, induced magnetic fields in the direction of the applied magnetic field. Incontrast with this behavior, diamagnetic materials are repelled by magnetic fieldsand form induced magnetic fields in the direction opposite to that of the appliedmagnetic field. Paramagnetic materials include most chemical element sandsome compounds; they have a relative magnetic permeability slightly greaterthan (i.e., a small positive magnetic susceptibility) and hence are attracted to magnetic fields. The magnetic moment induced by the applied field is linear inthe field strength and rather weak. It typically requires a sensitive analyticalbalance to detect the effect and modern measurements on paramagneticmaterials are often conducted with a SQUID magnetometer.

FerromagnetismFerromagnetism is the basic mechanism by which certain materials (suchas iron) form permanent magnets, or are attracted to magnets. In physics,several different types of magnetism are distinguished. Ferromagnetism (alongwith the similar effect ferromagnetism) is the strongest type and is responsible forthe common phenomena of magnetism in magnets encountered in everydaylife. Substances respond weakly to magnetic fields with three other types ofmagnetism, para magnetism, diamagnetism, and anti ferromagnetism, but theforces are usually so weak that they can only be detected by sensitiveinstruments in a laboratory. An everyday example of ferromagnetism isa refrigerator magnet used to hold notes on a refrigerator door. The attraction between a magnet and ferromagnetic material is "the quality of magnetism firstapparent to the ancient world, and to us today".

Semiconductor physicsDoping :-

Doping is the process of adding impurities to intrinsic semiconductors to alter their properties. Normally Trivalent and Pentavalent elements are used to dope Silicon and Germanium. When an intrinsic semiconductor is doped with Trivalent impurity it becomes a P-Type semiconductor. 

Diagram of PN-junction:-

Rectifier:-A rectifier is an electrical device that converts alternating current, which periodically reverses direction, to direct current, which flows in only one direction. The process is known as rectification, since it "straightens" the direction

NPN transistor symbol:-

PNP transister symbol:-

Difference between extensive and intensive

Extensive properties, such as mass and volume, depend on the amount of matter being measured. Intensive properties, such as density and color, do not depend on the amount of the substance present. Physical properties can be measured without changing a substance's chemical identity.

Difference between p type and n type semi conductor:-

n-type Semi-Conductor

It is an extrinsic semi-conductor which is obtained by doping the impurity atoms of Vth group of the periodic table to the pure Ge and Si semi-conductor. The impurity atoms added, provide extra electrons in the structure and are called donor atoms. The electrons are majority carriers and holes are minority carriers. The electrons density (ne) is much greater than the hole density (nh) i.e.>> nh. The donor energy level is close to the conduction band and for away from the valence band. The Fermi-energy level lies in between the donor energy level and conduction band.

P-type Semi-Conductor

It is an extrinsic semi-conductor which is obtained by doping the impurity atoms of III group of the periodic table to the pure Ge and Si semi-conductor. The impurity atoms added, create vaccines of electrons (i.e. holes) in the structure and are called acceptor atoms. The holes are majority carriers and electrons are minority carriers. The holes density (nh) is much greater than the electrons density (ne) i.e.>> ne. The acceptor energy level is close to the Valence band and for away from the Conduction band. The Fermi-energy level lies in between the acceptor energy level and valence band. These are the differences between n type and p type semiconductors. If you know more, then please discuss.

PN junction diode and its VI characteristics

-There are three possible  biasing  conditions and two operating regions for the typical PN-Junction Diode, they are: zero bias, forward bias and reverse bias.

The VI characteristics of PN junction diode in forward bias are non linear, that is, not a straight line. ... When forward bias is applied to the diodethen it causes a low impedance path and permits to conduct a large amount of current which is known as infinite 

Half wave rectifier-

Half Wave Rectification. A rectifier is a circuit which converts the Alternating Current (AC) input power into a Direct Current (DC) output power. The input power supply may be either a single-phase or a multi-phase supply with the simplest of all the rectifier circuits being that of the Half Wave Rectifier.

Full wave rectifier

A Full Wave Rectifier is a circuit, which converts an ac voltage into a pulsating dc voltage using both half cycles of the applied ac voltage. It uses two diodes of which one conducts during one half cycle while the other conducts during the other half cycle of the applied ac voltage.

Types of substance conductor, insulator and semi conductor

The glass, wood, mica, diamond are the examples of an insulator. A metal having conductivity which is between conductor and an insulator is called semiconductor. The silicon and germanium are the examples of a semiconductor.

Modern physics LASER:-

The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".

Defination of Laser:-

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".

Optical fibre:-

A long thin thread of glass through which information, sound, data, etc. can be sent in the form of light.

Ionization energy of hydrogen atom:-

For a hydrogen atom, composed of an orbiting electron bound to a nucleus of one proton, an ionization energy of2.18 × 10−18 joule (13.6 electron volts) is required to force the electron from its lowest energy level entirely out of the atom.

Fibre works on principle:-

Optical Fibre : Principle and Working.

The optical fibre is a device which works on the principle of “total internal reflection” by which light signals can be transmitted from one place to another with a negligible loss of energy.

Nanometerial:-

Nanomaterials describe, in principle,materials of which a single unit is sized (in at least one dimension) between 1 to 1000 nanometres (10−9meter) but usually is 1 to 100 nm (the usual definition of nanoscale). ...Materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties.

Example of nanomaterials are carbon nanotube, nanoparticle, metal rubber, quantum dots, nanopores and many more. Nanotechnology, shortened to "nanotech", is the study of the controlling of matter on an atomic and molecular scale.

Characterstics of LASER:.

Laser radiation has the following important characteristics over ordinary light source. They are: i) mono chromaticity, ii) directionality, iii) coherence and iv) brightness. (i) Mono chromaticity: A laser beam is more or less in single wavelength. ... So, laser radiation is said to be highly monochromatic.

On the other hand, in laser, all the emitted photons have the same energy, frequency, or wavelength. Hence, the light waves of laser have single wavelength or color. Therefore, laser light covers a very narrow range of frequencies or wavelengths.

Application of LASER:-Applications in Medical applications, welding and Cutting,

surveying, garment industry, laser nuclear fusion, communication, laser printing, CDs and optical discs, spectroscopy, heat treatment, barcode scanners, laser cooling.

Application of fibre:-

Applications. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication and cable television signals. Due to much lower attenuation and interference, optical  has large advantages over existing copper wire in long-distance, high-demand applications.

Application of nanotechnology

Medicine

Researchers are developing customized no particles the size of molecules that can deliver drugs directly to diseased cells in your body.  When it's perfected, this method should greatly reduce the damage treatment such as chemotherapy does to a patient's healthy cells.

Electronic

Nanotechnology holds some answers for how we might increase the capabilities of electronics devices while we reduce their weight and power consumption.

Food

Nanotechnology is having an impact on several aspects of food science, from how food is grown to how it is packaged. Companies are developing nanomaterials that will make a difference not only in the taste of food, but also in food safety, and the health benefits that food delivers. 

Fuel cells

Nanotechnology is being used to reduce the cost of catalysts used in fuel cells to produce hydrogen ions from fuel such as methanol and to improve the efficiency of membranes used in fuel cells to separate hydrogen ions from other gases such as oxygen.

Solar cell

Companies have developed nanotech solar cells that can be manufactured at significantly lower cost than conventional solar cells.

Batteries

Companies are currently developing batteries using nanomaterials. One such battery will be a good as new after sitting on the shelf for decades. Another battery  can be recharged significantly faster than conventional batteries.

Cleaner water

Nanotechnology is being used to develop solutions to three very different problems in water quality. One challenge is the removal of industrial wastes, such as a cleaning solvent called TCE, from groundwater. particles can be used to convert the contaminating chemical through a chemical reaction to make it harmless. 

Ionization potential:-

In physics and chemistry, ionization energy or ionisation energy, denoted Eᵢ, is the minimum amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated neutral gaseous atom or molecule.

Excitation

This is the energy required in ev to excite a ground state atom to its excited state. When electrons jumps from ground state level(n=1) to another another energy level(n=2) the corresponding energy is called 1stexcitation potential energy and corresponding potential is called 1stexcitation potential.

Stimulated absorption:-

Stimulated absorption occurs when a photon strikes an atom with just exactly the proper energy to induce an electronic transition between two energy states.

Spontaneous emission:-

spontaneous emission is the process in which a quantum mechanical system transitions from an excited energy state to a lower energy state and emits a quantised amount of energy in the form of a photon.

Stimulated emission:-Stimulated emission is the process by which an incoming photon of a specific frequency can interact with an excited atomic electron, causing it to drop to a lower energy level.