WHAT IS ESCAPE VELOCITY

escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero. It is the speed needed to "break free" from the gravitational attraction of a massive body, without further propulsion, i.e., without spending more fuel. For a spherically symmetric body, the escape velocity at a given distance is calculated by the formula where G is the universal gravitational constant (G = 6.67×10−11 m3 kg−1 s−2),...

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WHAT IS ENERGY

Energy is the capacity of a body to do work . energy is a property of objects, transferable among them via fundamental interactions, which can be converted in form but not created or destroyed. The joule is the SI unit of energy, based on the amount transferred to an object by the mechanical work of moving it 1 metre against a force of 1 newton. Work and heat are two categories of processes or mechanisms that can transfer a given amount of energy. The second law of thermodynamics limits the amount of work that can be performed...

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WHAT IS VELOCITY

Velocity is the rate of change of the position of an object, equivalent to a specification of its speed and direction of motion, e.g. 60 km/h to the north. Velocity is an important concept in kinematics, the branch of classical mechanics which describes the motion of bodies. Velocity is a vector physical quantity; both magnitude and direction are required to define it. The scalar absolute value (magnitude) of velocity is called "speed",...

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WHAT IS DISTANCE

Distance, or farness, is a numerical description of how far apart objects are. In physics or everyday usage, distance may refer to a physical length, or an estimation based on other criteria (e.g. "two counties over"). In mathematics, a distance function or metric is a generalization of the concept of physical distance. A metric is a function that behaves according to a specific set of rules, and is a concrete way of describing what it means for elements of some space to be "close to" or "far away from" each other. In...

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WHAT IS PHOTOELECTRIC EFFECT

The photoelectric effect is the observation that many metals emit electrons when light shines upon them. Electrons emitted in this manner may be called photoelectrons. According to classical electromagnetic theory, this effect can be attributed to the transfer of energy from the light to an electron in the metal. From this perspective, an alteration in either the amplitude or wavelength of light would induce changes in the rate of emission...

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WHAT IS OHM'S LAW

This law relates the current and potential difference with resistance as the constant of proportionality. Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance,  the usual mathematical equation that describes this relationship: where I is the current through the conductor in...

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GOD PARTICLES wrt MASS

One of the most active large research projects today is the search for an extremely small but energetic particle that is thought to be the key to understanding how mass appeared shortly after the Big Bang. The Higgs boson is a hypothetical elementary particle that has not been observed but, if found, would dramatically advance the 70-year development of a model of elementary particle interaction. Its existence was predicted along with other particles by the so-called Standard Model. The Standard Model describes how...

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WHAT ARE HIGGS BOSONS OR GOD PARTICLES

The Higgs boson or Higgs particle is an elementary particle initially theorised in 1964, whose discovery was announced at CERN on 4 July 2012.[7] The discovery has been called "monumental"[8][9] because it appears to confirm the existence of the Higgs field .:   The "God particle" is the nickname of a subatomic particle called the Higgs boson. In layman’s terms, different subatomic particles are responsible for giving matter different properties. One of the most mysterious and important properties is mass. Some particles,...

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WHAT ARE THE PROPERTIES OF PHOTON

Einstein explain photoelectric effect by  assuming that electromagnetic radiation travels through space in discrete quanta called photons . Thus photon is a quantum of electromagnetic radiation which always travels along straight paths with velocity equal to that of light and zero rest mass . Properties of photon                            The energy of a photon of frequency v is hv .                        ...

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WHAT ARE BLACK BODIES AND BLACK BODY RADIATIONS

Black body A body which completely absorb radiations of all wavelengths incident on it . A black body in thermal equilibrium (that is, at a constant temperature) emits electromagnetic radiation called black-body radiation. The radiation is emitted according to Planck's law, meaning that it has a spectrum that is determined by the tempera A black body in thermal equilibrium has two notable properties It is an ideal emitter: at every frequency, it emits as much energy as or more energy than any other body at the same temperature. It...

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WHAT IS QUANTUM MECHANICS

Quantum mechanics  deals the objects at microscopic level . means in QUANTUM MECHANICS  we study the particles which are of very small size i.e  which are of atomic size where lengths are of the orders of about one angstroms to fermis .Quantum mechanics was found successful in giving satisfactory explanation to many observed facts related  to micro objects . The development of quantum mechanics took place  in two stages - First stage - This stage began with the Max Planck's hypothesis . According...

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WHAT ARE THE APPLICATIONS OF LASERS

There are lot of applications of lasers in the every field of life .These can be discussed as - LASER WELDING  This type of welding competes very well with the other standard techniques , like arc welding ,resistance welding  electron beam welding etc . The highly collimated beam of a laser can be further focused to a microscopic dot of extremely high energy density for welding and cutting. The automobile industry makes extensive use of carbon dioxide lasers with powers up to several kilowatts for computer controlled...

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BASIC TYPES OF LASER

The classification of laser is done on the basis of active material used in them .Accordingly various types of lasers are :           SOLID STATE LASER     GAS LASER    SEMICONDUCTOR There are many types of lasers available for research, medical, industrial, and commercial uses.  Lasers are often described by the kind of lasing medium they use - solid state, gas, excimer, dye, or semiconductor. Solid state lasers have lasing material distributed...

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WHAT IS THE PRINCIPLE OF LASER ACTION

To make a laser we need three things : Active material Pump source Resonator                  This can be explained as - the block diagram  can be drawn as Fig. 2: Basic Laser system A representative laser system is shown in Figure (2). It consists of three basic parts. An active medium with a suitable set of energy levels to support...

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WHAT ARE THE APPLICATIONS OF SUPERCONDUCTORS

There are a lot of applications of superconductors - The superconductors are used to perform logic and storage functions in computers . Superconducting magnets are some of the most powerful electromagnets known. They are used in MRI/NMR machines, mass spectrometers, and the beam-steering magnets used in particle accelerators. They can also be used for magnetic separation, where weakly magnetic particles are extracted from a background of less or non-magnetic particles, as in the pigment industries. Electrical machines...

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WHAT ARE SUPERCONDUCTORS

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a particular temperature is called CRITICAL TEMPERATURE . The electrical resistivity of most metals and many alloys drops suddenly to zero at very low temperature .This phenomena is called  SUPERCONDUCTIVITY . Superconductivity was discovered by Dutch physicist Heike Kamerlingh Onnes . The critical temperature for mercury is 4.2 K . And the critical temperature...

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WHAT IS LASER .

 LASER -Light amplification by stimulated emission of radiation A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation . When an electron absorbs energy either from light (photons) or heat (phonons), it receives that incident quantum of energy. But transitions are only allowed in between discrete energy levels . This leads to emission lines and absorption lines. When an electron is excited from a lower to a higher energy level,...

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THE ELECTRIC LINES OF FORCE

Definition The path traced by a unit positive charge free to move under the effect of an electric field is called electric line of force . or                   Electric lines of force can be defined as a way or path, it may be straight or curved, so that the tangent at any point to it gives the direction of the electric field intensity at that...

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WHAT ARE THE PROPERTIES OF ELECTRIC CHARGE

 As electric charge is fundamental property  .It displays following  properties - Electric charge is quantised . Electric charge is conserved . Electric charge is a scalar quantity. This is associated with mass always . This is additive i.e. its sum total can be found by an algebraic sum . Electric charge remains unaffected by the motion .   Like mass, electric charge in a closed system is conserved. As long as a system is impermeable, the amount of charge inside it will neither increase nor decrease;...

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DEFINITION OF ELECTRIC CHARGE

The electric charge may be defined as that property of matter due to which the matter is able to exhibit electric , magnetic ,and electromagnetic effects . A basic property of some elementary particle of matter  by virtue of which they develop electrical influence is called electric charge . A charge can be positive or negative  . Electric charge can not exist on its own , it always requires a mass to sit on . But electric monopole is possible i.e. positive and negative charge can exist independently e.g. an electron...

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TYPES OF CLASSICAL OPTICS

Classical optics is divided into two main branches: geometrical optics and physical optics. In geometrical, or ray optics, light is considered to travel in straight lines, and in physical, or wave optics, light is considered to be an electromagnetic wave. Geometrical optics can be viewed as an approximation of physical optics which can be applied when the wavelength of the light used is much smaller than the size of the optical elements...

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WHAT IS OPTICS

Definition : The branch of physics which deals with light is known as optics . Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.    Most optical phenomena can be accounted for using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice.   Optical...

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WHAT ARE LIGHT WAVES

Light waves are electromagnetic waves . They do not need a material medium for their propagation . Light waves are transverse waves by nature .They show the phenomena of reflection , refraction , dispersion , diffraction , interferences ,and polarization  .  Light waves move fastest in vacuum and their velocity decreases in denser medium .Light waves  travel faster in air as compared to solid and liquid .there is no effect of change in temperature or humidity on velocity of light . Light is radiant energy,...

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WHAT ARE LONGITUDINAL AND TRANSVERSE WAVES

Longitudinal and transverse waves  LONGITUDINAL WAVES :  If the direction of the wave and its constituent particles is same i.e they are alligned in same direction then the wave is known as longitudinal wave . TRANSVERSE WAVE :  If the direction of wave and its constituent particles is perpendicular to each  other  ,then the wave is known as transverse wave . Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves. Through solids, however, it...

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PROPAGATION OF SOUND WAVES

Sound propagates through compressible media such as air, water and solids as longitudinal waves and also as a transverse waves in solids (see Longitudinal and transverse waves, below). The sound waves are generated by a sound source, such as the vibrating diaphragm of a stereo speaker. The sound source creates vibrations in the surrounding medium. As the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of sound, thus forming the sound wave. At a fixed distance from the...

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VARIOUS PHYSICS SYMBOLS , MEANINGS AND UNITS

Symbol Meaning SI unit of measure area meter squared (m2) magnetic vector potential amplitude acceleration meter per second squared (m/s2) or (m s−2) magnetic flux intensity also called the magnetic field density or magnetic induction tesla (T), or equivalently,   weber per square meter (Wb/m2) capacitance farad (F) heat capacity joule per kelvin (J K−1), or equivalently, joule per degree Celsius (J °C−1) constant...

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