Final answer:
Magnetic fields are generated by moving charges or changing electric fields. Ampere's law is an equation that describes this phenomenon. Therefore, options 2 and 3 are correct.
Step-by-step explanation:
Magnetic fields are produced by:
1) the magnetic permeability of vacuum
- This is not correct. The magnetic permeability of vacuum, denoted as μ₀, is a constant that relates the magnetic field to the magnetization in a vacuum. However, it does not produce magnetic fields.
2) the "spin" property of some fundamental particles
- Correct. The spin property of fundamental particles, such as electrons, contributes to the generation of magnetic fields.
3) moving electric charges
- Correct. According to Ampère's Law, the flow of electric current (i.e., moving electric charges) generates a magnetic field.
4) large electric fields
- This is not correct. While changing electric fields can induce magnetic fields (according to Maxwell's equations), large electric fields alone do not produce magnetic fields.
Therefore, options 2 and 3 are correct.