Answer:
Explanation:
Magnetic field due to circular wire at the center = μ₀ I / 2 r
I is current and r is radius . μ₀ = 4π x 10⁻⁷.
field B₁ due to inner loop
B₁ = 4π x 10⁻⁷ x 12 / 2 x .20
= 376.8 x 10⁻⁷
Field due to outer loop
B₂ = 4π x 10⁻⁷ x I / 2 x .30
For equilibrium
B₁ = B₂
376.8 x 10⁻⁷ = 4π x 10⁻⁷ x I / 2 x .30
I = 18 A.
The direction should be opposite to that in the inner wire . It should be anti-clockwise.
