Question

Two long parallel wires are separated by a distance of 2 m. They carry a current of 1A each in opposite direction. The magnetic induction at the midpoint of a straight line connecting these two wires is:

• A. Zero
• B. $2\times {10}^{-7}T$
• C. $4\times {10}^{-5}T$
• D. $4\times {10}^{-7}T$

Answer 1

The correct option is D $4\times {10}^{-7}T$

As magnetic field are in same direction we simply add, therefore,

$B=B_1+B_2$
=$\frac{{\mu }_0{i}_1}{2\pi r_1}+\frac{{\mu }_0{i}_2}{2\pi r_2}$
=$\frac{2\times {10}^{-7}\times 1}{1}+\frac{2\times {10}^{-7}\times 1}{1}$
=$4\times {10}^{-7}T$