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Electromagnetic Induction

description

  • Fleming's right hand rule
  • Direct current (DC)
  • Alternating current (AC)

notes

ELECTROMAGNETIC INDUCTION:-

Faraday made an important breakthrough by discovering how a moving magnet can be used to generate electric currents.

When a conductor is set to move inside a magnetic field or a magnetic field is set to be changing around a conductor, electric current is induced in the conductor. This is just opposite to the exertion of force by a current carrying conductor inside a magnetic field. In other words, when a conductor is brought in relative motion vis-à-vis a magnetic field, a potential difference is induced in it. This is known as electromagnetic induction.

Electromagnetic induction can be explained with the help of Fleming’s Right Hand Rule. If the right hand is stretched in a way that the index finger, middle finger and thumb are in mutually perpendicular directions, then the thumb shows the direction of movement of the conductor, index finger shows the direction of magnetic field and the middle finger shows the direction of induced current in the conductor. The directions of movement of conductor, magnetic field and induced current can be compared to three mutually perpendicular axes, i.e. x, y and z axes.

The mutually perpendicular directions also point to an important fact that the when the magnetic field and movement of conductor are perpendicular, the magnitude of induced current would be maximum.

Electromagnetic induction is used in the conversion of kinetic energy into electrical energy.

The direction of the induced current can be  identified by Flemings right hand rule.

FLEMINGS RIGHT HAND RULE:-

Stretch the thumb, forefinger and middle finger of right hand so that they are perpendicular to each other. If the forefinger indicates the direction of the magnetic field and the thumb shows the direction of motion of conductor, then the middle finger will show the direction of induced current. This simple rule is called Fleming’s right-hand rule.

AC & DC CURRENT:-

-The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically.

-Most power stations constructed these days produce AC.

-In India, the AC changes direction after every 1/100 second, that is, the frequency of AC is 50 Hz.

-An important advantage of AC over DC is that electric power can be transmitted over long distances without much loss of energy.

 

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Shaalaa.com | Electromagnetic Induction part 1 (Introduction)

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Electromagnetic Induction part 1 (Introduction) [00:03:04]
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