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P3 4.1c – Student practical sheet
Strength of electromagnets
Aim
To investigate the factors that affect the strength of an electromagnet.
Equipment
You will need the following equipment:
●
ammeter
●
low voltage d.c. power supply
●
box of paper clips
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soft iron bar or iron nail
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thin cotton-covered copper wire
(several metres)
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sticky tape
What you need to do
1
2
3
Plan an investigation to determine how the following factors affect the strength of an
electromagnet.
●
The current in the coil.
●
The number of turns of wire in the coil.
Your plan should include:
●
the apparatus you will use
●
how you will measure the strength of the electromagnet
●
whether or not you need to carry out any preliminary tests and what these will be
●
how you will choose the range and intervals for your independent variables
●
how you will make sure your test is fair
●
how you will assess the precision and reliability of your results
●
what you will do to make sure your investigation is carried out safely
Show your plan to your teacher before you start.
Using the evidence
1
Record your results in a table and draw a graph. (4 marks)
2
What can you conclude from your results? (2 marks)
Evaluation
3
How effective was your method of measuring the strength of the electromagnet? (2 marks)
4
How reliable are your results? (2 marks)
Extension
5
Suggest how an electromagnet can be used as an ammeter, and explain how your idea works.
(2 marks)
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