# Flemings Left Hand Rule

micro
I m finding Difficulty in applyng flemings left hand rule to
DC otor and AC Motor.Dats y i never like Applied Physics.

mathmike

DeathKnight
Well I think when motion is produced by a current in a conduct, we use Flemings Left Hand rule to predict the direction of motion. Whereas, when motion is producing current we use FLEMINGS RIGHT HAND RULE. It’s same as Flemings Left Hand rule but this time you do it with your right hand to predict the direction of induced emf or current. In this case the thumb will show the direction of motion, forefinger will show the direction of magnetic field and the middle finger will show the direction of the induced emf or current.

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ArielGenesis
Personally I don't think the left hand or the right hand rule give any thing more useful then the grip rule. And so I ignore the left and right rule and only use the grip as it apply for both.

Step to use the grip rule instead the right of left:

1. Determine the direction of the current and use the grip rule to show the magnetic field.

2. See if the magnetic field from the current intersenct with the permanent magnet. Determine the motion caused.

do it the other way round if motion is given and wearching for the field.
the same step could be use also to determine the position of permanent magnet.

SankalpSethi
The left hand rule is a very simple rule to apply -
1) Stretch out the thumb , first finger and the middle finger (!) such that they are mutually perpendicular.
2) If the middle finger is pointing towards the direction of flow of current(I) , then the first finger shows you the direction of the Magnetic field (B) and the thumb gives you the direction of the force experienced on the conuctor.
While applying , make sure you take 2 fingers in the same plane , the third one shall automatically give you the direction in terms of UPWARDS OR DOWNWARDS.
This rule is basically used for determining direction of the quantities and not the magnitude.

The Right hand rule also is applied in a similar way , the diff. is that the thumb gives you the direction of flow of induced current.
Ciao.