 Level: International Baccalaureate
 Subject: Physics
 Word count: 1427
Investigating the induced emf with the number of windings and different heights
Extracts from this document...
Introduction
Investigating the induced emf by changing the number of windings
Introduction and design
This investigation is based on Faraday’s experiments on electromagnetic induction. What we want to investigate is to see if there are any connections between the number of windings and the induced emf. In Faraday’s experiment, he concluded that a changing magnetic field can induce an emf.
A hypothesis is that the coils of wire have a constant magnetic field. If we than increase the coils then we will get a stronger magnetic field. So, if we double the number of windings on the coil, we should get a magnetic field with a strength doubled. So the induced current and emf should also be doubled with a doubled magnetic field. Also, the height will influence the change in magnetic flux when it enter the fields and the proposal would be an increase in height will increase the emf
So the research question would be: “investigating the induced emf in with the number of windings and different heights”
The variables in this experiment are height, acceleration, voltage (emf), current, time and magnetic field.
 The dependent variables are the time, voltage (emf) and current.
Middle
Graph 9: Used a coil of 600 windings with a height of 33 cm
Graph 10: Used a coil of 600 windings with a height of 33 cm
Graph 11: Used a coil of 1200 windings with a height of 33 cm
Graph 12: Used a coil of 1200 windings with a height of 33 cm
Here comes a table with the maximum and minimum voltage on every graphs:


 
Number of windings (loops)  
0  0,000  0,000  0,000  0,000  
300  0,488  0,566  0,488  0,586  
600  0,957  1,113  0,942  1,084  
1200  1,939  2,017  1,953  2,026 



Conclusion
In graph 13, we see the graph is fitting really well with a correlation of 0,9987 which is almost perfect. This shows the function is fitting good and it is proportional to each other.
In graph 14, the graph does fit well to a certain extent with a correlation of 0,9838. This function also shows the proportional relationship between the variables.
Conclusion and evaluation
To conclude the experiment, we have seen how a magnet can induce an emf in different coils of windings. The results tell me that the number if windings on the coils is proportional with the induced emf. , is the induced emf and N is the number of windings
We also find out that the height of the magnet is proportional to the induced emf.
, is the induced emf and H is the height of the magnet.
This experiment has many ways for improvements:
 The interval which the magnet drops through the coil is short, which make it less accurate. Maybe we could lengthen the magnet or coil to get a longer time interval
 We should collect more sufficient points for the height, which is necessary to draw a accurate graph
 It could have been some error while dropping the magnet, it may have touched the coil on its way through it.
 Maybe use a mechanical device to drop the magnet to get a more accurate height.
This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.
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