Fig. 7.1 shows three bars of steel, A, B and C.
Fig. 7.1
A student is given the three pieces of steel. Two of the pieces are magnetised and one piece is unmagnetised.
Describe and explain how the student determines which piece is unmagnetised using only the three pieces of steel.
Fig. 8.1 shows a coil wound around a steel bar that is initially unmagnetised.
Any appropriate power supply can be connected between the terminals A and B . No other apparatus is available.
Fig. 8.1
Describe
- how the steel bar can be magnetised,
- how the steel bar can then be demagnetised.
magnetised:
demagnetised:
Fig. 7.1 shows two magnets and the gap between the N pole of one magnet and the S pole of the other magnet.
Fig. 7.1
On Fig. 7.1, draw three lines to show the pattern and direction of the magnetic field in the gap.
Fig. 7.2 is a repeat of Fig. 7.1 showing the two magnets.
On Fig. 7.2, draw the position of a plotting compass needle when it comes to rest in the gap between the N pole and the S pole.
Explain why the needle comes to rest in this position.
Describe a method of demagnetising a bar magnet.
Describe a method of demagnetising a bar magnet.
Which metal can be attracted by a magnet?
zinc
lead
iron
copper
State what is meant by a magnetic field.
The diagram shows part of the magnetic field between two bar magnets.
Which statement about the ends of the magnets is correct?
X and Y are both N poles.
X and Y are both S poles.
X is an N pole and Y is an S pole.
X is an S pole and Y is an N pole.
Define the direction of a magnetic field.
Fig. 7.2 is a repeat of Fig. 7.1 showing the two magnets.
On Fig. 7.2, draw the position of a plotting compass needle when it comes to rest in the gap between the N pole and the S pole.
In which way are a bar magnet and an electromagnet similar?
A bar magnet and an electromagnet are always magnetised when stored.
A bar magnet and an electromagnet can both be used to separate magnetic and non-magnetic materials.
A bar magnet can be made of steel and an electromagnet uses a steel core.
The magnetic field strength of a bar magnet and of an electromagnet can both be varied.
Two circuits are set up as shown. The iron rods are placed close together and are able to move.
What happens to the size of the gap at X when switch S is closed?
It decreases.
It decreases then increases.
It increases.
It does not change.
Students are asked for a statement about magnetic fields.
Three statements are listed.
1 A magnetic field is described as a region in which a stationary electric charge experiences a force.
2 The direction of a magnetic field at a point is the direction of the force on an S pole at that point.
3 The relative strength of a magnetic field is shown by the spacing of the magnetic field lines.
Which statements are correct for magnetic fields?
1, 2 and 3
1 and 2 only
2 and 3 only
3 only