An electromagnet is a coil of wire through which a current can be passed. An electromagnet can be switched on and off. Suggest one situation where this would be an advantage over the constant field of a permanent magnet.
Important Questions on Magnetism
A solenoid has a magnetic field similar to that of a bar magnet.
The diagram shows a bar magnet and a solenoid arranged so that they repel one another. Copy the diagram, leaving some space around it. Label the poles of the solenoid.
A solenoid has a magnetic field similar to that of a bar magnet.
Add the field lines to your diagram to represent the magnetic field of the bar magnet and the solenoid.
Magnet A and B, shown in the diagram, attract each other.
The S pole of magnet A has been marked. On a copy of this diagram, mark the polarities of other poles, using the letters N or S.
A soft-iron rod and a steel rod each have coils around them. Both rods are initially un-magnetised. The coils are attached to circuits, as shown in the below diagram.
Copy the table below, referring to the soft-iron rod and the steel rod shown in the above diagram.
Use the following statements to complete the table.
Magnetised loses its magnetism keeps its magnetism
| Switch closed | Switch open | |
| Soft iron | ||
| Steel |
A soft-iron rod and a steel rod each have coils around them. Both rods are initially un-magnetised. The coils are attracted to circuits, as shown in the second diagram.
Which words apply to the force between the rods when the switches are closed? Choose one from:
no force attractive force repulsive force
