Siddharth Nair
10 C
PHYSICS LAB REPORT
STRENGTH OF AN ELECTROMAGNET
AIM:
To investigate the factors that affects the strength of an electromagnet.
THEORY:
An electromagnet is a magnet that runs on electricity. Unlike a permanent magnet, the strength of an electromagnet can easily be changed by changing the amount of electric current that flows through it. The poles of an electromagnet can even be reversed by reversing the flow of electricity.
An electromagnet works because an electric current produces a magnetic field. The magnetic field produced by electric current forms circles around the electric current, as shown in the diagram below:
If a wire carrying an electric current is formed into a series of loops, the magnetic field can be concentrated within the loops. The magnetic field can be strengthened even more by wrapping the wire around a core. The of certain materials, such as , and , each behave like tiny magnets. Normally, the atoms in something like a lump of iron point in random directions and the individual magnetic fields tend to cancel each other out. However, the magnetic field produced by the wire wrapped around the core can force some of the atoms within the core to point in one direction. All of their little magnetic fields add together, creating a stronger magnetic field.
As the current flowing around the core increases, the number of aligned atoms increases and the stronger the magnetic field becomes. At least, up to a point. Sooner or later, all of the atoms that can be aligned will be aligned. At this point, the magnet is said to be saturated and increasing the electric current flowing around the core no longer affects the magnetization of the core itself.
FACTORS AFFECTING THE STRENGTH OF AN ELECTROMAGNET:
- Distance between each turn of the coil: If the distance between two turns in the coil of a solenoid is decreased, the electromagnetism increases. This is because; the air trapped between two turns forms an insulating barrier that doesn’t allow the passage of current, if the distance was more.
- Strength of the electric current: To make an electromagnet function correctly electricity has to be passed through it. Therefore if the current is increase the strength of the magnet will increase and vice versa.
- Number of turns of the coil: If the number of turns on the solenoid is increased then the strength of the magnet is increased and vice versa.
ROUGH PLAN:
Above I have already described the three factors that affect the strength of the magnet. Therefore in this experiment I will investigate only 2 of the factors and see the effect it has on the strength of the magnet. The two factors are:
- Number of turns of the coil.
- Strength of the current
For the first experimental factor I planned to wrap a wire around the electromagnet and then pass current through it and then see how many nails it attracts. I will keep reducing the number of turns and then see the effect on the nails it has.
For the second experimental factor, I will again make an electromagnet by wrapping the wire around the iron core. Therefore in this I will see by varying the current how much of the mass is attracted to the electromagnet.
BASIC SET-UP OF THE APPARATUS:
APPARATUS:
- Power pack
- Piece of iron
- Sand paper
- Metre- rule
- Clamp stand
- 20 iron nails/ paper clips
- Digital balance
- 30cm of copper wire.
- A long iron nail
- Small Petri dish
- Plastic cup
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Peer Reviews
Here's what a star student thought of this essay
Quality of writing
While the piece is of a high standard, a few sections would benefit from being rewritten, such as the final conclusion. Phrases such as “very less†in the factor 1 - fair test section should be the focus of this. Technical terms are used sparsely, but are always used well and add to the piece. More technical language could be added, but it shouldn’t be a cause for concern if left as it is.
Level of analysis
You have successfully proven your initial theory, but you need more proof – which can be obtained from the results you have already gathered; however, it would improve the reliability of your results by repeating your experiment and taking an average of the results and adding error bars to your graph. This would also help explain why your points do not exactly lie on the line of best fit if they are inside the error range. Without analysis of the errors, it does not show you understand the experiment as well as you should.
Response to question
The facts in this experiment are good, but the analysis is largely missing. You have demonstrated well every step of this experiment. You have detailed your pre-experiment hypothesis and analysed your findings and compared them to your original findings in the second experiment, but nothing in the first section. There is not enough analysis in the analysis section for either experiment let alone both. You need to talk about errors, the cause of errors, and the science behind proving your hypothesis. More appropriate diagrams could help add to the text.
