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Author Archives: admin

Does the sun do any work on earth?

No work is done on the earth revolving around it in perfectly circular orbit.The earth revolves around the sun due to gravitational force of attraction between the sun and the earth.This gravitational force provides centripetal force to the earth to revolve around the sun.Since centripetal force is always directed towards the centre of the orbit.This centripetal force is always perpendicular ...

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Is energy quantized in classical physics?

No,according to classical wave theory the emission of electromagnetic radiations from the surface is continuous. So energy is not quantized in classical physics.But according to photon theory the emission of electromagnetic radiation from the surface is discontinuous.Energy is quantized and radiations are emitted in the form of bundles of energy is called quanta or photon.Each photon has energy given as: ...

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bohr model for hydrogen

 Bohr’s theory of the  hydrogen atom: The Rutherford model of atom and the experimental formula of atomic spectra helped Bohr is solving the problem of atomic structure.In 1913 he proposed a model for the structure of a hydrogen atom based on his experimental observations.  Bohr’s postulates: Neil Bohr based his theory of hydrogen atom on the following three postulates. 1:The ...

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Inductance of solenoid and toroid

What is solenoid? Solenoid is defined as:”A long tightly wound cylindrical conducting wire is called solenoid.” Magnetic field due to solenoid: Consider a solenoid having n turns per unit length.When current passes through the solenoid ,magnetic field is produced inside the solenoid which is directed along the axis of solenoid.The magnetic field in space outside the solenoid is so weak ...

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Natural Radioactivity and its applications

What is Natural-radioactivity? All the elements beyond hydrogen and helium were made in nuclear reactions in the interiors of stars or in explosive supernovas. Both radioactive and stable nuclides are created in these processes. The solar system is composed of nuclides that were formed about 4.5×109 years ago. (How this is determined is discussed later in this section). Most of ...

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Types of radioactive decay:Alpha,beta and gamma decay

What is radioactive decay? “Radioactive decay  is the process by which the nucleus of an unstable atom loses energy by emitting radiation, including alpha particles, beta particles, gamma rays and conversion electrons.” Most of the nuclides that have been identified are radioactive.That is,they spontaneously emit a particle,transforming themselves in the process into a different nuclide . In this section we discuss the two ...

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Ampere’s circuital Law in differential form with Applications

What is ampere’s law? According to this law “The line integral of magnetic field B along a closed path due to current is equal to the product of the permeability of free space and the current enclosed by the closed path”. Mathematically it is expressed as: Where μ0=permeability of free space i=current flowing through the conductor. Proof: Consider a straight ...

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How to find density with mass and volume?

What is Density? “Mass per unit volume  of a material is called density.”Density is an important property of any material.A homogeneous material such as ice or iron has the same density throughout.We use  (the Greek letter rho) for density.If a mass m of homogeneous material has volume V ,the density  is: Two objects made of the same material have the ...

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gravitational potential energy:Definition,derivation & examples

Gravitational potential energy: We know that a particle gains or loses kinetic energy because it interacts with other objects that exert forces on it.During any interaction,the change in a particle’s kinetic energy is equal to the work done on the particle by the forces that act on it. In many situations it seems as through energy has been stored in ...

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Viscosity of fluids and Poiseuille’s law with applications

What is Viscosity? “Viscosity is the  internal friction in a fluid.”Viscous forces opposes the motion of one portion of a fluid relative to another.Viscosity is the reason it takes effort to paddle a canoe through calm water,but it is also the reason the paddle works.Viscous effects are important in the flow of fluids in pipes,the flow of blood,the lubrication of ...

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