Question

1. electromagnets only produce a magnetic field when which of the following events happen?

current flows.

heat is applied.

the object is struck.

another magnet is nearby.

Explanation:

Define electromagnetism and its source

Using the Electromagnetism knowledge point
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Unlike permanent magnets, the magnetic field of an electromagnet can be turned on or off.

Identify the role of electric current

Using the Electric Current knowledge point
The magnetic field is generated by moving electric charges. When an electric current flows through a wire (typically wound into a coil), it creates a magnetic field around the wire. If the current stops flowing, the magnetic field disappears.

Evaluate the given options

• Current flows: This is the fundamental requirement for an electromagnet to generate a magnetic field.
• Heat is applied: Applying heat does not generate a magnetic field in a coil; in fact, excessive heat can damage the insulation of the wire.
• The object is struck: Striking an object is a method used to demagnetize permanent magnets, not to activate electromagnets.
• Another magnet is nearby: While a nearby magnet will interact with an electromagnet, it is not what causes the electromagnet to produce its own magnetic field.

Answer:

• Current flows. (Correct answer)
• Heat is applied.
• The object is struck.
• Another magnet is nearby.