Magnetic Field Produced by Straight Currents Video Lessons

Concept

# Problem: Two long wires are parallel and carry current in opposite directions. The currents are 8.0 and 12 A and the wires are separated by 0.40 cm. The magnetic field in tesla at a point midway between the wires is:A. 0B. 4.0 × 10–4C. 8.0 × 10–4D. 12 × 10–4E. 20 × 10–4

###### FREE Expert Solution

Magnetic field around a wire carrying current:

$\overline{){\mathbf{B}}{\mathbf{=}}\frac{{\mathbf{\mu }}_{\mathbf{0}}\mathbf{i}}{\mathbf{2}\mathbf{\pi }\mathbf{r}}}$

Right-hand rule: Thumb points in the direction of current, fingers curl in the direction of the current.

Applying the right-hand rule to wires carrying current in opposite directions, the magnetic field between them is directed in the same direction.

89% (223 ratings)
###### Problem Details

Two long wires are parallel and carry current in opposite directions. The currents are 8.0 and 12 A and the wires are separated by 0.40 cm. The magnetic field in tesla at a point midway between the wires is:

A. 0

B. 4.0 × 10–4

C. 8.0 × 10–4

D. 12 × 10–4

E. 20 × 10–4