Answer: 2 x 10-5 T.
- A 2 x 10-5 T
- B 4 x 10-5 T
- C 8 x 10-5 T
- D 2 x 10-4 T
Correct answer: A. 2 x 10-5 T
Explanation: B = mu0 I / (2 pi r) = 4pi x 10-7 x 10 / (2 pi x 0.1) = 4x10-6 / 0.2pi = 2x10-5 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.