Question

question 18 of 30 which of the following produces a magnetic field? a a moving piece of unmagnetized iron b a stationary electric charge c a moving particle with a net neutral charge d a moving electric charge

Explanation:

A moving electric charge produces a magnetic field (Ampère's law). Stationary charges (B) produce electric fields. Neutral particles (C) have no net charge to generate a field. Magnetized iron (A) has a field but movement isn't required, and the question focuses on production, with D being the fundamental cause.

Answer:

D. A moving electric charge