The past several weeks have consisted of our probe experiment. The probe is a representation of Faraday’s Law, which is a law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce electromotive force (EMF). As stated in the lab, “the greater is the change in magnetic flux, the greater are the currents and voltages.” The faster you shake the tube, the greater the generated voltage. Conversely, the slower you shake the tube, the lower the voltage generated.
1 generator (magnet that moves back and forth inside a coil of wire)
1 voltage probe
1 NXT adaptor
NXT
Labview VI
Here’s how we did it:
- Labview software, per usual: attach the voltage probe to the metal part of the flashlight’s coil wire.
- Connect NXT to the computer.
- Shake the flashlight in a thirty second time interval and record the sum of the square of the voltages as data points.
- Account and adjust the number of shakes, and record.
- Convert and calculate data in Microsoft Excel (sum of the squares of the voltages).
- Repeat functions two more times at different shake frequencies. Our lab instructor informed us that two trials would suffice in reaching the goal of this lab.
Here’s what we found:
Final remarks
As you can see, our second trial demonstrates the significant amount of SSV’s recorded from 70 shakes, at 85.50668 SSV. The huge increase between this and the previous set of zero shakes (0.917578 SSV) proves Faraday’s Law true. Thanks to these findings it can be confirmed that, for example, 35 shakes at the same frequency would result in an SSV exactly half that of 70 because of the correlation found in our trials. It is important to note also that differences of shake vigorousness would affect the voltage to varying degrees, so unless you can perfectly replicate the same force on the shaking probe you can expect some spuriousness in repeated experiments. Overall, however, it is certainly clear that more total shakes determines a high SSV.
Your trials have proven that Faraday’s claims are valid. Nice work!