Answer: 2.5×10⁻³ T.
- A 1.25×10⁻³ T
- B 2.5×10⁻³ T
- C 5×10⁻³ T
- D 2.5×10⁻⁴ T
Correct answer: B. 2.5×10⁻³ T
Explanation: B = μ₀nI = 4π×10⁻⁷·1000·2 ≈ 2.5×10⁻³ T.
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.