The magnetic field (d→B) due to a small element (dl)

The magnetic field (d^→_B) due to a small element (dl) at a distance (^→_r) and element carrying current i is

According to Biot Savart law,

d^→_B =	μ₀In		i(d^→_ℓ × ^→_r)
	4π		r³

d^→_B =	μ₀	i		d^→_l × ^→_r
	4π			r

d^→_B =	μ₀	i²		d^→_l × ^→_r
	4π			r²

d^→_B =	μ₀	i²		d^→_l × ^→_r
	4π			r

d^→_B =	μ₀	i		d^→_l × ^→_r
	4π			r³