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Electricity & Megnetism

Electric field and electric field lines

What is electric field? “The electric field is a region around a charge in which it exerts electrostatic force on another charges.” According to coulomb’s law ,if a unit positive charge q0 (call it a test charge) is brought near a charge q (call a field charge) placed in space,the charge q0 will experience a force.The value of this force depends ...

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Kirchhoff’s voltage law definition problems and solutions

What is Kirchhoff’s Voltage Law? Kirchhoff’s voltage law is a fundamental circuit law that states that the algebraic sum of all the voltages around a closed path is zero or, in other words,the sum of the voltage drops equals the total source voltage. In an electric circuit, the voltages across the resistors(voltage drops) always have polarities opposite to the source ...

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Faraday’s law of electromagnetic induction

Faraday’s law of induction was discovered through experiments carried out by Micheal Faraday in England In 1831 and by Joseph Henry in the United States at about the same time. *Even through Faraday published his results first, which gives him priority of discovery, the SI unit of inductance is called the henry (abbreviation H). On the other hand, the SI ...

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Lenz’s Law of electromagnetic induction

What is Lenz’s Law? “The direction of induced current is always so as to oppose the change which causes the current.” A mathematical expression of Faraday’s law of electromagnetic induction was derived as: ε = – N ΔΦ/Δt The minus sign in the expression is very important.It has to do with the direction of the induced emf.To determine the direction we ...

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Electromagnetic radiation spectrum

What is Electromagnetic Spectrum: The word spectrum comes from a Latin word meaning “form” or “appearance”. Other familiar words from the same root include “spectacle” and “species.” Newton introduced word to describe the rainbow-like image that resulted when a beam of sunlight passed through a glass prism. Today we speak of the electromagnetic spectrum to indicate the many different kinds ...

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Wheatstone bridge strain gauge

The Wheatstone Bridge: The Wheatstone bridge circuit is widely used to precisely measure resistance. Also, the bridge is used in conjunction with transducers to measure physical quantities such as strain,temperature , and pressure. Transducers are devices that sense a change in a physical parameter and convert that change into an electrical quantity such as a change in resistance. For example, a ...

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Difference between Inductor and capacitor

What is Inductor? When a length of wire is formed into a coil,it becomes a basic inductor. The term coil and inductor are used interchangeably.Current through the coil produced an electromagnetic field, as illustrated. The magnetic lines of force around each loop (turn) in the winding of the coil effectively add to the lines of force around the adjoining loops, ...

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Electromagnetic induction applications

Electromagnetic Induction: As soon as Oersted discovered that electric currents produce magnetic fields,many scientist began to look for the reverse effect, that is, to cause an electric current by means of a magnetic field. In 1831 Michael Faraday in England and at the same time Joseph Henry in USA observed that an emf is set up in a conductor when ...

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What is modulation and demodulation

What is modulation? Until the process of superimposing a low frequency (long wave) voice information component on a high frequency (short wave) carrier signal was perfected,the most widely used form of communication was a system based on the transmission of a continuous wave (CW) signal.With this system,the signal was interrupted periodically (Morse code) to produce a coded message.The CW system ...

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How does electric motor works

What is Electric Motor? An electric motor is an electromechanical device that converts electrical energy into mechanical energy.Electrical motors can be run as generators and vice versa, although this is not always practical. The Motor Principle: When a current-carrying conductor is located in an external magnetic field perpendicular to the conductor, the conductor experiences a force perpendicular to itself and ...

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