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“FORCE ON CURRENT CARRYING CONDUCTOR WHEN PLACED IN MAGNETIC FIELD”, CHARGED PARTICLES WHEN MOVE INSIDE A MAGNETIC FIELD EXPERIENCED A FORCE.

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ELECTRONS CONSTITUTE CURRENT IN THE CONDUCTOR.EACH ELECTRONS EXPERIENCE FORCE DUE TO THE EXTERNAL MAGNETIC FIELD .TOTAL FORCE ON THE ELECTRONS IS EQUAL TO THE FORCE ON THE WHOLE CONDUCTOR.

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Let ‘l’ be the length , ‘A’ be the area of cross section of the wire . Also , n is the no. of electrons per unit volume of the conductor. I is the steady current ,v is the drift velocity of electrons . B is the magnitude of external magnetic field and it makes angle θ with the axis of the conductor., Force on an electron , f = -e (v ×B)-----------(1), Total force on N electrons , F=N . f = n .A .l . f where N =n. a. l, So, F= n. A. l. e(v ×B)-----------------(2), Since , I= n. A .e. v, F = I (l × B), F= B I L sinθ, Case:, When θ=O or 180 i. e the direction of magnetic field is parallel to the axis of the conductor, F=O no force is experienced., When θ=90 ,the direction of magnetic field is perpendicular to the axis of the conductor. Maximum force is experienced on the conductor. F= BI l

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FORCE BETWEEN TWO PARALLEL STRAIGHT CURRENT CARRYING INFINITE LONG WIRES :

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HENCE, TWO STRAIGHT PARALLEL CONDUCTORS CARRYING CURRENT IN THE SAME DIRECTIONS ATTRACT EACH OTHERS . IF THE CURRENTS FLOW IN DIFFERENT DIRECTIONS ,THE TWO WIRES WILL REPEL EACH OTHERS.

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DEFINITION OF 1 AMPERE OF CURRENT:, Using the relation , F= μ₀I1I2/2πr, 1 A of current is the current flowing across the two parallel wires separated by a distance 1 metre apart in free space experiencing a force of 2×10⁻⁷N per metre on each.