Physics
A copper wire is held between the poles of a magnet. There is a switch provided to reverse the current in the wire. Also, the polarity can be changed. In how many directions can the force act on the wire?
Electro-Magnetism
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Answer
According to Fleming’s Left Hand Rule, the direction of force on a current-carrying conductor placed in a magnetic field depends on:
- Forefinger → Direction of magnetic field (from North to South)
- Middle finger → Direction of current
- Thumb → Direction of the force (motion) on the wire
In this case:
- The current in the wire can flow in 2 directions (forward or reversed using the switch).
- The magnetic field can also be in 2 directions (from North to South or South to North, depending on polarity).
So, the force on the wire can act in:
2 (current directions) x 2 (field directions) = 4 different directions
Thus, the force on the wire can act in 4 possible directions.
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