Experiment’s goal

While doing this kind of experiment, students support to learn and understand the relationship between light intensity and the voltage output of the solar cell, as well as the relationship between the wavelength of light and the voltage output of the solar cell.

 

Equipment

• One solar cell
• One voltage probe
• One NXT adaptor
• NXT with light sensor
• One light source
• Labview VI vi
• Ruler
• Colored film filters
• Excel sheet

 

Set up

• Plug battery on NXT with light sensor
• Plug the NXT adaptor to NXT with light sensor through a USB cable (code number 1)
• Connect voltage probe to a solar cell by cables (red-red) and (black-black)
• Connect USB cable between computer and NXT with light sensor

 

Experimental processes

1) Measure voltage output by light intensity at different distances

• Open Labview
• Put Solar on top of flashlight which is zero distance.
• Use ruler to measure the distance between flashlight and solar cell.

• Choose 4 more different distances to measure
• Press START on the Labview program to record the voltage ouput
• At the first experiment, we only got 10 numbers of data for each test
• Open Excel File after each test to calculate the average those ten numbers to get one final result.
• To calculate average, we tried to get the sum of 10 numbers then divided by ten.

For example : (0.39587 + 0.34455 + 0.33172 + 0.42153 + 0.31889 + 0.33172 + 0.33172 + 0.37021 + 0.38304 + 0.31889)/10 = 0.354814 V

• Or you can calculate on Excel Spreadsheet using its functions
• Finally, we come up with with this final result for the first experiment

 

 

After this experiment, my teammate and I learned that when the flashlight and solar cell are far away from each other, the light will be less power and the voltage ouput will decrease. However, it is a little weird at distance 4 cm and 6 cm where the voltage output increase and decrease at distance 8 cm. Over all, we got a nice graph and data.

 

2) Measure voltage output by light intensity at the same distance with different colored film filters

• Open the labview program
• We chose 4 cm as the only distance in this experiment
• There is 4 colored film filters: orange, light blue, dark blue, and light purple
• Put each of them in front of the flashlight for each test.
• Press START to record the data
• Open Excel Spreadsheet and calculate average of 10 numbers for each color as what we did in the first experiment.
• Finally, we came up with this result for the second experiment

 

 

In this experiment, we made a mistake at the first test. We though that it would come up 10 numbers each time as what we did in the first experiment. However, the numbers countinued to exceed 10 numbers so my teammate decided to press STOP. It immidiately affected our data. We tried to take the last 10 numbers but I though that we couldn’t get a correct data. Then, we tried to stop at the number 10 for the next test. When we got the average of voltage output for each of colored film filters, I assumed that the voltage ouput would decrease at any ligh colored film filters such as light blue and light purple as what we got.

 

Conclusion

After doing this kind of experiment, I learned that the voltage output can be afftected by distance and color. When the distance is far away from the light source, the voltage output will also decrease because the light is not powerful and strong at the logh distance. Additionally, even though the light source and solar cell stay at the same direaction for whole experiment, the voltage output still be changed by the different color. When we use dark color, the voltage output will increase and vice versa. It is same situation when we wear black and red in a hot day, we will feel more hot because dark colors can get more temperature and energy than the light one.