Magnetism & Electromagnetism (AQA GCSE Combined Science: Synergy: Physical Sciences): Exam Questions

FIGURE 15 shows a wire held in place between the poles of a permanent magnet.

The wire is connected to an electrical circuit.

When the switch is closed, the wire moves.

Explain why. [4 marks]

The length of wire in the magnetic field around the permanent magnet is 0.050 m.

The potential difference across the ends of the wire is 0.14 V.

The resistance of the wire is 0.040 Ω.

The magnetic flux density of the magnetic field around the permanent magnet is 22 mT.

Calculate the force on the wire.

Use the Physics Equations Sheet.

Force = ______________________ N

Permanent magnets have a magnetic field around them.

The Earth has a magnetic field.

Which part of the Earth’s internal structure creates the magnetic field?

Tick (✓) one box.

A magnetic compass contains a bar magnet.

Which diagram shows the magnetic field around a bar magnet?

Tick (✓) one box.

A student wrapped insulated wire around an iron bar to make an electromagnet.

Figure 8 shows the electromagnet held in a clamp and connected to a circuit.

When the switch was closed, the electromagnet attracted paper clips.

The student investigated how the number of turns of wire on the iron bar affected the strength of the electromagnet.

This is the method used:

1. Wrap 20 turns of wire around the iron bar

2. Hold the paper clips near the bottom of the electromagnet

3. Close the switch

4. Count the number of paper clips the electromagnet picks up

5. Open the switch

6. Repeat steps 1 to 5, but with more turns of wire around the iron bar

The student used the same value of current throughout the investigation.

What type of variable was the current?

Tick (✓) one box.

Table 4 shows the results. When there was no wire wrapped around the iron bar, no paper clips were picked up.

Table 4

Draw a ring around the anomalous result in Table 4.

The student did not take another reading to replace the anomalous result.

What did the student do with the anomalous result when calculating the mean?

Figure 9 is a graph of the results.

How many paper clips would be picked up when 70 turns of wire are wrapped around the iron bar?

Number of paper clips = _______________

The investigation was repeated using a larger current.

Draw a line on Figure 9 to show the expected results.

A student investigated the magnetic effect of an electric current.

The student placed two iron rods inside a rectangular coil.

Figure 1 shows the equipment.

Figure 1

When the power supply is switched on there is a current in the rectangular coil.

Complete the sentence.

When there is a current in the rectangular coil, there is a magnetic field around the coil.

The magnetic field has a similar shape to the magnetic field around a __________________.

The two iron rods repel each other when there is a magnetic field around the coil.

Explain why.

The two iron rods are replaced with copper rods.

The two copper rods remain stationary when there is a magnetic field around the coil.

Give one reason why.

The student made an electromagnet by:

• wrapping a coil of wire around an iron bar

• connecting the coil of wire to a power supply.

The student investigated how the current in the electromagnet affected the strength of the electromagnet.

Figure 2 shows the electromagnet.

Figure 2

Identify magnetic poles A and B in Figure 2.

The student arranged a newtonmeter and an iron disc above the electromagnet.

Figure 3 shows the equipment.

Figure 3

The power supply is switched off.

Why is the newtonmeter reading 2.0 N?

Tick (✓) one box.

The student switched the power supply on and then increased the current in the electromagnet.

The iron disc was not touching the electromagnet, but the reading on the newtonmeter changed.

Explain why.

The student recorded the readings on the newtonmeter as the current increased.

Figure 4

The student wrapped twice as many turns of wire around the iron bar and repeated the investigation.

Draw a line on Figure 4 to show the expected results.

This question is about magnetism.

Which two materials are magnetic?

Tick (✓) two boxes.

Describe how you could find the magnetic field pattern of a permanent bar magnet.

A student investigates how the number of turns of wire on a solenoid affects the strength of the solenoid.

To test the strength of the solenoid she looks at how many paper clips the solenoid could lift.

Figure 3 shows the setup equipment.

She keeps the current through the coil constant throughout the experiment.

Figure 3

Table 3 shows the student's results.

Table 3

Use the data from Table 3 to complete the graph in Figure 4.

• The first two points have been plotted for you.

• Draw a line of best fit.

Figure 4

Describe the pattern shown in the graph.

Use your graph to predict how many paper clips the solenoid will pick up when 80 turns of wire are used.

Number of paper clips picked up = _________________

Explain why this reaction is a redox reaction.

Figure 5 shows an electromagnet being used to lift a car in a scrapyard.

Figure 5

An electromagnet is made up of a solenoid.

Figure 6 shows a solenoid.

Figure 6

Draw the magnetic field of the solenoid on Figure 6.

In a scrapyard, an electromagnet is used to lift and release cars so they can be moved around.

Suggest two ways a solenoid could be made to lift and release cars in a scrapyard.

Explain why each suggestion would be useful in the scrapyard.

The area around a magnet is called the magnetic field.

The Earth has a magnetic field.

What causes the Earth's magnetic field?

Tick (✓) one box.

Figure 4

What will happen in each case when the poles of two magnets are brought close together?

Opposite poles brought together: __________________________

Same poles brought together: ______________________________

Figure 5 shows an electromagnet being used to lift a car in a scrapyard.

Figure 5

An electromagnet is a solenoid.

Explain why it is better to use an electromagnet rather than a permanent magnet in a scrapyard.

You should include a comparison of the properties of electromagnets and permanent magnets in your answer.