See how the induced voltage changes when you pass a magnet through a coil of wire

        When you drop a magnet from a certain height it always has potent ional energy in itself from you. It is calculated like this:  

        Potential energy = Mgh

        When the magnet falls it has kinetic energy and it is calculated like this:

        Kinetic energy = 0.5mv2

        This means that the speed is directly proportional to the square route of height.

I will use 5 different height and they will be 0, 10, 20, 30, and 40. I will take four readings for each height and take an average so it will be a fare test and I will get the most accurate results possible. I will put 40 coils at the start and decrease them by ten. I will keep the height constant which will be 20. I choose 20 because it is in the middle of my dropping heights and it is very comfortable to drop it from there. When I decrease the number of coils I will not cut the unused coil off because that would be an unfair test because every time I drop the magnet I need it to go through the same length of wire every single time.

        

Apparatus

1. A magnet attached to a 20 cm 1 cm by 1 cm thickness of wood.
2. A cylinder, which is 15 cm long.
3. A 10 by 10 cm size carpet to protect the magnet falling.
4. A cathode-ray oscilloscope.
5. A connecting wire.
6. A power cable.
7. 5 metres of wire.
8. Card paper.
9. A 2-metre ruler.
10.  Two clamps.

Diagram of the apparatus

        Method

1. Set up the apparatus as shown.
2. The ruler has to be at the height where the coils are the highest.
3. Height 0 is not the ground it is the highest point of the coils.
4. Measure the right height from which you will drop the magnet.
5. Drop the magnet and measure what voltage you get out.
6. Repeat this for every single height and different number of coils.
7. Don’t change the coils when you change the height you need to keep one of them constant.

Obtaining

What was the voltage I got from dropping the magnet through a coil of wire?

The change in height when I drop the magnet

The height (cm)                the voltage out (mv)                Average (mv)

                                Reading taken

                                          1st       2nd     3rd     4th  

The change in the number of coils, the constant height is 20 (cm)

No. Of coils                        the voltage out (mv)                Average (mv)

   

                                  Reading taken

                                                 1st   2nd    3rd    4th  

                                

                        Evaluation

        I predicted that the voltage would increase as I increase the height from which I drop the magnet and the number of coils increases too. My prediction was correct and I got the results I expected. Faraday’s law said that the voltage you get out will increase when you.

1. Increase the number of coils.
2. Have a stronger magnet.
3. Move the magnet through the coil faster.

        The graph, which shows the change in height from which I drop the magnet, is a straight line, which shows that the voltage is proportional to the height in some way. The graph had an upward trend all the time meaning that the voltage output increased every time I dropped the magnet from higher. As I predicted before that the voltage will increase as you increase the height also I said that the voltage increase when I increase the number of coils. The second graph is where I kept the height constant but I changed the number of coils I had round the cylinder. The constant height was 20 and the highest number of coils was 40. When I changed the number of coils I did not cut off the unused piece left I kept it so the electrons in the wire move the same distance all the time and it will be a fair test. The graph also was a straight line and showed some sort of proportion between the number of coils and voltage. I predicted that the voltage would increase as you increase the number of coils and I was right because the graph had an upward trend.

                                Evaluation

                My investigation went well and I had one anomalous result. It occurred on the changing height experiment on the last height of 40 cm. It did not fit into the pattern so I thought it was an anomalous result. I took average for each height and when I changed the number of coils because it was very hard to measure the voltage out and to release the magnet from the right height. The anomalous result was from 40 centimetres height and that the hardest height from, which you can drop the magnet. The oscilloscope was not accurate in measuring voltage the scale of it was simply too large to get very accurate results.         

The repetition of the experiment

If I had to repeat the experiment I would firstly search for more accurate and simpler equipment to the oscilloscope because the readings which were taken from it were not very accurate and that’s why I took an average of all of mine results so I can get some sort of idea of what they are meant to be. I would also change the height because it is very hard to drop the magnet from the correct height.