Question

1. State the right hand palm rule and cork screw rule for finding the direction of magnetic field, and derive an expression for the force ailing between two parallel conductors carrying current.​

Answer 1

The right hand rule states that, to find the direction of the magnetic force on a positive moving charge, the thumb of the right hand point in the direction of v, the fingers in the direction of B, and the force (F) is directed perpendicular to the right hand palm.

Answer 2

Right hand palm rule

If a current carrying conductor is imagined to be held within the grip of  the right and if the direction of current through the conductor is indicated by the thumb, then the other fingers will curl in the direction of the magnetic field.

Maxwell's corkscrew rule

If we imagine a right handed corkscrew to be driven along the direction of current in a conductor, then the direction in which it rotates, gives the direction of the magnetic field.

Force acting between two parallel conductors carrying current

Let d be the perpendicular distance between two long, straight parallel current carrying conductors.

Let $i_{1}$ current flowing through conductor 1 and $i_{2}$ current flowing through conductor 2.

Due to current $i_{1}$ the magnetic field at a distance r will be

          B = $\frac{u_{o} }{4\pi } \frac{2i_{1} }{d}$

from the relation F = Bil, we get force in conductor 2,

          F = $\frac{u_{o} }{4\pi } \frac{2i_{1}i_{2} }{d}$

This equation gives the definition of international ampere.