Which statement best describes magnetic fields?

• A. A magnetic field is a vector field produced by moving electric charges and magnetic dipoles, and it exerts forces on moving charges and magnetic moments.
• B. A magnetic field is identical to an electric field and always points from positive to negative charge.
• C. A magnetic field exists only inside permanent magnets and is zero everywhere outside them.
• D. A magnetic field is a scalar field that acts only on stationary electric charges.

Answer: (A)

Verified step by step guidance

1. Understand that a magnetic field is a physical field produced by moving electric charges (such as currents) and intrinsic magnetic moments (like those of electrons).
2. Recognize that magnetic fields are vector fields, meaning they have both magnitude and direction, and they influence other moving charges and magnetic dipoles by exerting forces.
3. Recall that magnetic fields are not identical to electric fields; electric fields originate from electric charges and point from positive to negative charges, whereas magnetic fields arise from moving charges and magnetic moments.
4. Note that magnetic fields are not confined only inside permanent magnets; they extend into the space around magnets and current-carrying wires.
5. Remember that magnetic fields do not act on stationary charges; they exert forces only on moving charges or magnetic dipoles, distinguishing them from electric fields which can act on stationary charges.