How do I know when to use the right hand Fleming's Rule and when to use left hand Fleming's Rule?

Asked by Rohan Rawal | 13th Jul, 2014, 12:21: PM

Expert Answer:

Fleming’s left-hand rule gives the direction of magnetic force acting on a conductor whereas Fleming’s right-hand rule is used to find the direction of induced current.Fleming's left-hand rule is used for electric motors while Fleming's right-hand rule is used for electric generators.

An electric current and magnet field exist in an electric motor, and they lead to the force that creates the motion , and so the left hand rule is used which gives the direction of magnetic force acting. In an electric generator, the motion and magnetic field exist and they lead to the production of an electric current , and so the right hand rule is used which helps us to find direction of induced current.

Fleming’s right-hand rule :

According to this rule, “Stretch the thumb, forefinger and middle finger of the right hand such that they are mutually perpendicular to each other. If the forefinger points indicates the direction of the magnetic field and the thumb indicates the direction of motion of the conductor, then the middle finger will indicate the direction of induced current in the conductor”.

Fleming’s left-hand rule :

According to this rule, “Stretch the thumb, forefinger and middle finger of the left hand such that they are mutually perpendicular to each other. If the forefinger points in the direction of magnetic field and the middle finger indicates the direction of the current, then the thumb will indicate the direction of motion or the force on the conductor”.

Answered by Jyothi Nair | 14th Jul, 2014, 08:56: AM

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