Answer: From south to north inside.
- A From south to north inside
- B From north to south inside
- C Radially outward
- D Circular
Correct answer: A. From south to north inside
Explanation: Inside a solenoid, field lines run from south to north (from one end to the other, along the axis).
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.