Magnetism is the force exerted by magnets when they attract or repel each other - Leaving Cert Physics - Question c - 2021

To plot the magnetic field around a bar magnet, follow these steps:

1. Apparatus: Gather a bar magnet, a piece of paper, a compass, and iron filings.
2. Procedure: Place the bar magnet on a flat surface and cover it with the sheet of paper. Use the compass to trace the direction of the magnetic field by marking the position of the compass needle at various points around the magnet.
3. Observation: After marking points, remove the paper and sprinkle iron filings over it. Gently tap the paper so that the filings align themselves along the magnetic field lines.
4. Conclusion: Draw lines connecting the dots marked from the compass. This will create a visual representation of the magnetic field, showing that it emanates from the north pole and curves to the south pole.

The diagram should depict a straight current-carrying conductor with concentric circles around it, indicating the magnetic field lines. The lines should be directed in a circular manner, clockwise or counter-clockwise, depending on the direction of the current flow.

To demonstrate that a current-carrying conductor experiences a force in a magnetic field, the student could use the following approach:

1. Apparatus: Set up a simple circuit using a power source (e.g., a battery), connecting wires, and a strip of metal (the conductor, such as a piece of aluminum foil).
2. Procedure: Connect the circuit and ensure that the conductor lies within an externally applied magnetic field (e.g., between the poles of a magnet).
3. Observation: As current flows through the conductor and it is placed in the magnetic field, the conductor will experience a mechanical force, which may cause it to move or deflect.
4. Conclusion: This effect demonstrates the interaction between the magnetic field and the current-carrying conductor.

One common use of magnets is in compasses, which are used for navigation and orientation. Another general application is in electronic devices, such as radios and cars, where magnets are utilized in speakers and motors.