JEE Main 2026 Physics question
A current of 30 A each flows in opposite directions in two conducting wires, placed parallel to each other at a distance of 8 cm. The magnetic field at the mid point between the two wires is μT. (μ₀/4π=10⁻⁷ N/A²)
Answer: (B)
Solution
Each wire gives B=μ₀I/(2πd)=2×10⁻⁷×30/0.04=1.5×10⁻⁴ T at the midpoint (d=4 cm). For opposite currents the fields add: B=3×10⁻⁴ T=300 μT.