Answer: Produces essentially the same magnetic field pattern outside, since both behave as equivalent magnetic dipoles.
- A Produces a noticeably weaker external field, since coiled current loops behave quite differently from a permanent magnet
- B Produces a field mainly inside itself, with little field reaching the space outside
- C Produces essentially the same magnetic field pattern outside, since both behave as equivalent magnetic dipoles
- D Produces a field that points radially outward rather than along an axis
Correct answer: C. Produces essentially the same magnetic field pattern outside, since both behave as equivalent magnetic dipoles
Explanation: A current-carrying solenoid behaves as a magnetic dipole equivalent to a bar magnet of the same magnetic moment, producing essentially the same external field pattern, including a similar dipole field along its axis.
Magnetic field of a bar magnet: field lines emerge from the north pole and re-enter at the south pole outside the magnet, forming continuous closed loops. Image: Geek3, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Bar magnets, Earth's magnetism, and how different materials respond to an external magnetic field - diamagnetic, paramagnetic, and ferromagnetic behaviour.