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Author Archives: admin

Impedance and reactance

Circuits with capacitors and inductors are more complicated than the resistive circuits we talked about earlier ,in that their behavior depends on frequency:A “voltage divider ” containing a capacitor or inductor will have a frequency dependent division ratio.In addition ,circuits containing these components (known collectively as reactive components),”corrupt” input waveforms such as square waves,as we just saw. However,both capacitors and ...

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Eddy current testing principle

What is eddy current? A current induced in a conductor when subject to a varying magnetic field.Such currents are a source of energy dissipation (eddy current loss) in alternating current machinery.The reaction between the eddy currents in a moving conductor and the magnetic in which it is moving is such as to retard the motion.This property of eddy currents is ...

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Radioactive carbon dating

What is dating? Any of several methods for determining the age of archaeological and fossil remains,rocks,etc,by measuring some property of the organic or inorganic matter that changes with time.This property may be dependent on some aspect of nuclear decay,such as the decay of the radiocarbon or the uranium series ,thermo luminescence ,or electron spin resonance.These aspects are studied by radiometric ...

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Thermal and chemical effects of current

Thermal effects: Joule’s law of heating: “The heat produced in a conductor is: (1) Directly proportion the square of current passing through the conductor,(H ∝ I²) keeping R and t constant; (2) Directly proportion to the resistance of the conductor (H ∝ R) keeping I and t constant;and (3)Directly proportional to the time of flow of current (H ∝ t) keeping I and ...

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What is difference between excitation and ionization potentials?

Excitation potential: The potential required to lift an electron from ground state to some higher state is called excitation potential. Or If the energy supplied to an electron is such that the electron is lifted from its ground state to one of the higher allowed orbits,the atom will be excited and the energy supplied is called excitation energy or excitation ...

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What are some applications of a step up transformer?of a step down transformer?

Applications of a step up transformer: For Transmission of electric power from power station to consumer,voltage is step up by using step up transformer.It minimizes the power loss in transmission line. Applications of a step down transformer: Step down transformer decrease the voltage to a safe value at the end of the transmission line where the consumer of electric power ...

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Why would power distribution systems be less effective without alternating current?

Most larger power distribution systems are AC.The power is transmitted from power stations at much higher voltage to minimize the power loss.At the end of the line where the consumer is located,the voltage level is reduced to a safe value for domestic use.The crucial factor is that it is much easier to increase and decrease AC voltage than DC,so AC ...

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Definition of motion in physics

Motion and its types physics: “A body is said to be in motion,if it changes its position with respect to its surroundings.” Surroundings are the places in its neighborhood where various objects are present.The state of rest or motion of a body is relative.For example,a passenger sitting in a moving bus is at rest because he is not changing his ...

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Moment of inertia units

Moment of inertia: Moment of inertia is defined as:”The sum of the products of the mass of each particle of the body and square of its perpendicular distance from axis.”For a rigid body moving about a fixed axis,the laws of motion have the same form as those of rectilinear motion,with moment of inertia replacing mass,angular replacing linear velocity,angular momentum replacing ...

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Ultrasound frequency range

What is ultrasonics? The study and application of mechanical vibrations with frequencies beyond the limits of hearing of the human ear i.e ,with frequencies about 20 kHz and upwards.There is no theoretical upper limit to the ultrasonic frequency ,although ultrasonic applications are usually restricted to about 20 MHz.Ultrasonic waves have the same basic properties as sound waves,both being examples of ...

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