Practise magnetic fields, forces, electromagnets and induction using pole labels, field-line diagrams, circuits and direction rules.
The region of space around a magnet is known as a magnetic field.
Which of these diagrams correctly represents the magnetic field around a bar magnet?
The diagram shows two bar magnets placed close together.
Which of these describes what happens to the two magnets?
nothing happens
they attract
they repel
they spin
Which of these magnet arrangements gives a uniform field between the poles?
State the name of a material that would be suitable for use as a permanent magnet.
Describe an investigation that could be used to determine the shape of the magnetic field around a bar magnet.
The diagrams show some equipment that the physicist Ørsted used in an investigation in 1820.
Diagram 1 shows the position of eight compass needles around a wire with no current in the wire.
The compass needles line up with and show the direction of the Earth's magnetic field lines.
Diagram 2 shows the position of the same compass needles when a current is in the wire.
Explain why the compass needles turn when the current is switched on.
Using evidence from the compass needles in diagram 2, draw on diagram 2 the shape and direction of a magnetic field line produced by the current in the wire.
Suggest what happens to the magnetic field when the current in the wire is reversed.
The current in the wire is turned off.
Diagram 3 shows the wire placed in a uniform magnetic field.
Diagram 3
The current is now switched on.
Draw an arrow to show the direction of the force on the wire.
The power supply in diagram 3 is replaced by an ammeter.
When the wire is moved, a current is detected.
Explain which direction the wire is moved in the magnetic field to produce a current in the wire.
Explain why a current is produced in the wire when the wire is moved in the magnetic field.