Practical questions
You will complete eight required practical activities if you are studying GCSE Physics and 21 if you are studying GCSE Combined Science. You could be asked questions about the methods, safety precautions you might take, results and conclusions of these experiments.
There are no required practicals in the Magnetism and Motor Effect topic.
Edexcel questions courtesy of Pearson Education Ltd.
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Dr Alex Lathbridge answers questions about practicals.
Sample question 1 - Foundation
Question
A student investigates the magnetic properties of three rods. Each rod is made of one of the following materials:
- soft iron
- steel
- wood
The student places each rod in a solenoid that is connected to a direct current power supply. The power supply is switched on for a short time. The student tests the magnetic strength of each rod by seeing how many paper clips it can pick up.
The number of paperclips picked up by each rod is shown in the table below.
| Rod | Before rod is placed in solenoid | When there is current in solenoid | 1 minute after current is switched off | 10 minutes after current is switched off |
| A | 0 | 0 | 0 | 0 |
| B | 0 | 6 | 1 | 0 |
| C | 0 | 8 | 7 | 7 |
| Rod | A |
|---|---|
| Before rod is placed in solenoid | 0 |
| When there is current in solenoid | 0 |
| 1 minute after current is switched off | 0 |
| 10 minutes after current is switched off | 0 |
| Rod | B |
|---|---|
| Before rod is placed in solenoid | 0 |
| When there is current in solenoid | 6 |
| 1 minute after current is switched off | 1 |
| 10 minutes after current is switched off | 0 |
| Rod | C |
|---|---|
| Before rod is placed in solenoid | 0 |
| When there is current in solenoid | 8 |
| 1 minute after current is switched off | 7 |
| 10 minutes after current is switched off | 7 |
Complete the table below to show which material (soft iron, steel or wood) each rod is made from and give the reason why. Part of the table has been done for you.
Use information from the table. [3 marks]
| Rod | Material | Reason |
| A | It is not magnetic because it does not pick up paper clips whether there is a current or not. | |
| B | ||
| C |
| Rod | A |
|---|---|
| Material | |
| Reason | It is not magnetic because it does not pick up paper clips whether there is a current or not. |
| Rod | B |
|---|---|
| Material | |
| Reason |
| Rod | C |
|---|---|
| Material | |
| Reason |
| Rod | Material | Reason |
| A | Wood | It is not magnetic because it does not pick up paper clips whether there is a current or not. |
| B | Soft iron | It only attracts paper clips when there is a current in the coil. |
| C | Steel | It attracts paper clips when there is a current in the coil and for some time after. |
| Rod | A |
|---|---|
| Material | Wood |
| Reason | It is not magnetic because it does not pick up paper clips whether there is a current or not. |
| Rod | B |
|---|---|
| Material | Soft iron |
| Reason | It only attracts paper clips when there is a current in the coil. |
| Rod | C |
|---|---|
| Material | Steel |
| Reason | It attracts paper clips when there is a current in the coil and for some time after. |
[3]
Sample question 2 - Higher
Question
A student investigates the relationship between the magnetic flux density and the electromagnetic force on a current-carrying wire.
The student has the equipment shown in the figure below:
The student varies the number of magnets and measures the force on the wire using the force meter.
The results are shown in the table.
| Number of pairs of magnets | Reading on force meter (N) |
| 1 | 0.0 |
| 2 | 0.0 |
| 3 | 0.1 |
| Number of pairs of magnets | 1 |
|---|---|
| Reading on force meter (N) | 0.0 |
| Number of pairs of magnets | 2 |
|---|---|
| Reading on force meter (N) | 0.0 |
| Number of pairs of magnets | 3 |
|---|---|
| Reading on force meter (N) | 0.1 |
The student decides that his equipment is not sufficiently sensitive.
Give three ways the student should develop his investigation to improve the quality of his results. [3 marks]
Any three from the following:
- use a higher current as the force depends on the current
- use stronger magnets
- use a force meter with a smaller range, eg 0.00 to 0.01
- use a longer distance from pivot to increase the moment of the force on the wire
[3]
Make sure you give three clear and separate answers. Remember that the force in the motor effect is increased by increasing the current and the field strength. You could also remember forces are increased by a greater distance from a pivot from your work on moments.