The horizontal componet of the earth's magnetic field at a certain place is `3.0xx10^(-5) T` and the direction of the field is from the geographic south to the geographic north. A very long straight conductor is carrying a steady current of 1A. What is the force per unit length on it when it is placed on a horizontal table and the direction of the current is south to north ?

Explanation

`F= Il xxB`
`F=IlB sin theta`
The force per unit length is
`f=F//l=I B sin theta`
When the current is flowing from south to north,
`theta= 0^(@)`
f=0
Hence there is no force on the conductor.