Question Detail
Question
magnetic induction of 20 mT is applied to long straight current carrying wire of radius 120mm. Find the current in the wire. Take μ₀/2π = 2×10⁻⁷ N/A².
Correct Answer
Option C is the correct answer.
Detailed Explanation
Using B = (μ₀ I)/(2π r). Given B = 20×10⁻³ T? That gives 12000A, not matching options. Assuming B=20 μT = 20×10⁻⁶ T, I = (B·2π r)/μ₀ = (20e-6 × 0.12)/(2e-7) = 12 A.
Hint
Check units: if B in μT, answer = 12A.