Answer: 2 × 10⁻⁷ N/m.
- A 2 × 10⁻⁷ N/m
- B 2 × 10⁻⁵ N/m
- C 1 N/m
- D 4π × 10⁻⁷ N/m
Correct answer: A. 2 × 10⁻⁷ N/m
Explanation: F/L = μ₀I₁I₂/2πd = 2 × 10⁻⁷ × (1×1)/1 = 2 × 10⁻⁷ N/m.
The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).
Concept context
Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.