The two long, straight wires carrying electric currents in opposite directions. The separation between the wires is 5.0 cm. Find the magnetic field at a point P midway between the wires.

Explanation

Solution:
figure 35.5
The right-hand thumb rule shows that the
magnetic field at P due to each of the wires is
perpendicular to the plane of the diagram and is going
into it. The magnitude of the field due to each wire is
` B = ((mu_0) i/2 pi d)`
` = ((2 xx (10^-7) TmA^-1)(10A))/ (2.5 xx 10^-2m)`
`= 80 mu T.`
` The net field due to both the wires is 2 xx 80 mu T = 160mu T`.
We can draw magnetic field lines on the pattern of electric field lines. A tangent to a magnetic field line gives the direction of the magnetic field existing at that point. For a long straight wire, the field lines are circles with their centres on the wire