Question

How is a magnetic field produced?

when an object has a electric charge
when electrons move through a circuit
when an electromagnetic field interacts with a magnet
when a current runs through a conductor

Answer 1

A magnetic field is produced specifically **when a current runs through a conductor**. This is due to the movement of electric charges (typically electrons in a circuit), which creates a magnetic field around the conductor according to Ampère's law.

In essence, the answers can be summarized as follows:

1. **When an object has an electric charge** - This doesn't directly produce a magnetic field by itself unless the charge is in motion.

2. **When electrons move through a circuit** - This is correct in that the movement of electrons (current) produces a magnetic field.

3. **When an electromagnetic field interacts with a magnet** - This relates to interactions between existing fields but does not directly describe how a magnetic field is produced.

4. **When a current runs through a conductor** - This is the most accurate and direct answer for producing a magnetic field.

Thus, the best choice from the given options is **when a current runs through a conductor**.