Question

Consider two parallel straight wires carrying electric current in opposite directions with the same magnitude of 2.0 A. The center-tocenter distance between the two wires is 5.0 mm. One wire is infinitively long and the other wire is 0.30 m long. Is the magnetic force between the two wires repulsive or attractive? What is the magnitude of the magnetic force between them? (Answer: ????????=4.8×10−5 ????????)

Answer 1

Answer:

Both wires repels to each other and magnitude of the magnetic force between them is $4.8 \times 10^{-5}$ N

Explanation:

Given:

Current $I =2$ A

Length of wire $l = 0.30$ m

Separation between two wire $a = 5 \times 10^{-3}$ m

Here current is in opposite direction so both wires repels to each other.

Force in current carrying wire is given by,

   $F = \frac{\mu_{o} I^{2} l }{2\pi a}$

Where $\mu_{o} = 4\pi \times 10^{-7}$

   $F = \frac{4\pi \times 10^{-7} \times (2)^{2} \times 0.3 }{2\pi \times 5 \times 10^{-3} }$

   $F = 4.8 \times 10^{-5}$ N

Therefore, both wires repels to each other and magnitude of the magnetic force between them is $4.8 \times 10^{-5}$ N