AQA · GCSE · Combined Science · Higher

Electromagnet lifting and moving the blocks

Q02.3 6 marks

Figure 4 shows a toy crane. The toy crane uses an electromagnet to pick up and move the blocks.

Toy crane controlled by a boy. The crane has a switch and an electromagnet hanging over blocks labelled as made from magnetic materials. — Figure 4

Explain how this electromagnet is able to pick up and move the blocks.

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Marking points

1 Explain that completing the circuit or closing the switch turns the electromagnet on.
2 State that current flows in the coil.
3 State that the current produces a magnetic field around the coil.
4 State that the iron core becomes magnetised.
5 Describe moving the electromagnet towards the blocks.
6 Explain that the magnetic blocks are attracted to the electromagnet.
7 Explain that moving the crane moves the attracted block.
8 Explain that switching off the current switches off the electromagnet.
9 Explain that the block is released when the electromagnet is switched off.
10 For the highest level, link the stages in a clear sequence from switching on, to attraction and movement, to switching off and release.

Full-mark answer

When the switch is closed the circuit is completed and current flows in the coil. This produces a magnetic field and magnetises the iron core, so the magnetic blocks are attracted to the electromagnet. The crane can then move the block. When the current is switched off the electromagnet is no longer magnetic, so the block is released.

Why this answer loses marks

The electromagnet is always magnetic and pulls the blocks up.

The answer misses that the electromagnet is controlled by current and can be switched off to release the block.

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