What is a magnetic field? A magnetic field is a region or area in space where the magnetic effect is felt, such as the attraction or repulsion of magnetic materials - Leaving Cert Physics - Question 10 - 2006

To demonstrate the magnetic field around a solenoid, we will set up the following:

Apparatus:

• Power source
• Electric circuit (solenoid)
• Iron filings

Procedure:

1. Connect the solenoid to the power source.
2. Turn on the current flowing through the solenoid.

Observation/Conclusion:

• Sprinkle iron filings around the solenoid. You will observe that the iron filings rearrange themselves into specific patterns demonstrating the direction and shape of the magnetic field lines.
• Use a compass to find the direction of the magnetic field.

Diagram: A labeled diagram should show the solenoid, iron filings, and patterns observed.

One use of an electromagnet is in electric bells.

An advantage of an electromagnet over an ordinary magnet is that the strength of the electromagnet can be varied, allowing for more precise control over its magnetic force.

An example of a device based on this effect is a speaker.

The direction of the force acting on the aluminum foil will reverse.

A larger force will be exerted on the aluminum foil.

There will be no force acting on the aluminum foil.

The force can be calculated using the formula: $F = I \times B \times L$ Substituting the values into the equation: $F = (1.5 \text{ A}) \times (3.0 \text{ T}) \times (0.1 \text{ m}) = 0.045 \text{ N}$ Thus, the force acting on the aluminum foil is 0.045 N.