Magnetism (Edexcel GCSE Physics)

A student uses plotting compasses to investigate the magnetic field between the poles of two bar magnets.

Figure 12 shows one of the plotting compasses and one of the bar magnets.

Figure 12

The student places the two magnets on a piece of paper with a pole of one magnet a few centimetres away from a pole of the other magnet.

The student places 20 plotting compasses on the paper near the magnets.

Figure 13 shows the direction in which each of the plotting compasses points.

Figure 13

i) Draw two rectangles on Figure 13 to show the positions of the two bar magnets.

Label the N-pole and the S-pole of each magnet.

[2]

ii) The student wants to determine the shape of the magnetic field for a larger area around the magnets.

Describe how the student should continue the investigation using just one plotting compass.

[3]

Two long, thin magnets are held with their N-poles facing each other.

The force, F, between the magnets can be calculated using the equation

where

K is a constant value

d is the distance between the magnets.

i) The magnets are 4.0 cm apart.

The force between the magnets is 1.2 N.

Calculate the value of K.

State the unit.

K = ............................... unit ........................[3]

ii) The magnets are held the same distance apart but with the N-pole of one magnet now facing the S-pole of the other magnet.

The value of K does not change.

State how the force would compare with the force in part (i).

[1]

Which of these is a magnetic material?

A student has

− a power pack

− a long piece of wire

− a stiff card

− iron filings

Describe how the student could use this equipment to show the shape of the magnetic field produced by a current in the wire.

You may draw a diagram to help with your answer.

Figure 5 shows two magnetic poles facing each other.

The magnetic field between the poles is uniform.

On Figure 5, draw the magnetic field lines between the two poles and show the direction of this magnetic field.

Figure 5

A student has a bar magnet, a piece of iron the same size as the magnet, and some paper clips.

Describe how the student could use these items to demonstrate temporary induced magnetism.

A student sets up the apparatus shown in Figure 9.

Figure 9

i) When the current in the solenoid is switched on, the solenoid attracts the iron nail.

Describe how the student could use this apparatus to investigate how the size of the current in the solenoid affects the force of attraction between the solenoid and the iron nail.

[4]

ii) The spring constant of a different spring is 24 N/m.

The spring is extended from its unstretched length by 12 cm.

Calculate the energy transferred in extending the spring by 12 cm.

Use an equation selected from the list of equations at the end of this paper.

energy transferred = ............................................... J[2]

Describe a method for drawing the magnetic field around a bar magnet using iron filings.

Define the term magnetic field.

State the direction of magnetic field lines in terms of poles.

Sketch the magnetic field lines for the two bar magnets shown in Figure 1.

Figure 1

A student is using compasses to investigate magnetic fields.

The student places two bar magnets as shown in Figure 1.

Figure 1

Draw field lines representing the magnetic field between the bar magnets.

The student rotates the bottom magnet 180°. Figure 2 shows their prediction drawn in their science work book.

Figure 2

Describe two mistakes in Figure 2.

The student attempts to look at the field lines by adding iron filings around the magnet.

Whilst collecting the iron filings, they spill some on the magnet.

Figure 3 shows a side view of the magnet and the filings. 

Figure 3

Explain why the iron filings are in this position. 

When attached to the magnet, a teacher shows the student that the iron filings can attract other iron filings.

One student claims that it must therefore be possible to repel other iron filings if they flip the magnet around.

Explain why this statement is incorrect.

Figure 13 shows a part of a machine used to separate steel cans from aluminium cans.

Figure 13

The cans are carried along a moving belt.

The belt goes around a roller.

The roller is a magnet.

Each can falls into one of the containers.

Explain how this machine separates the steel cans from the aluminium cans.

A student investigates magnetism using two toys as shown in Figure 14.

Figure 14

i) There is a magnet attached to the top of each toy.

The student moves the toy brick towards the toy car.

The magnet on the toy brick repels the magnet on the toy car.

On Figure 14, label the north pole and the south pole on the magnet attached to the toy brick.

[1]

ii) Explain why the toy car starts to move only when the toy brick gets near to the toy car.

[2]

iii) The student thinks that two magnets on top of each other will produce a magnetic field that is stronger than the magnetic field from a single magnet.

The student has a metre rule and more magnets available.

Describe how the student could develop this investigation to test this theory.

[4]