Is it true that some electrical activity produces electric fields but no magnetic fields?

The correct response is that it is false that some electrical activity produces electric fields but no magnetic fields. In electromagnetic theory, any time there is an electric current flowing — which is the movement of electric charges — it generates both an electric field and a corresponding magnetic field. This is described by Maxwell's equations, which illustrate the interrelationship between electric and magnetic fields.

Electric fields exist around static charges, which do not produce magnetic fields unless they are in motion or there is a change in the electric field over time. However, currents create a magnetic field due to the movement of electrons. Even if the current is steady, the magnetic field exists in conjunction with the electric field produced by the charge distribution.

Understanding this relationship between electric and magnetic fields is foundational in the design and application of various electrical systems, especially in telecommunications infrastructures, where both fields are critical for the operation of devices and transmission of signals. Thus, the assertion that some electrical activity can lead to electric fields without magnetic fields is not accurate within the framework of classical electromagnetism.