Physics 107 - Light Intensity I


First, go through worked example I and answer all of the questions. Work in pairs on this and hand in when you are done.


To develop a model relating intensity to the number of plastic sheets blocking the light, make measurements using a wide range of number of sheets. To get started


Once you have an initial set of data, consult with another group and decide what to do next to improve the quality of the data set. This could include, but are not limited to:
Based on your discussion, write down what you think is wrong with your data so far, and what you plan to do next, and then take more data.


Produce a semi-log plot of your data so far to qualitatively confirm whether or not it shows exponential decrease.

Again, confer with other about what extra data you might need to improve the semi-log scatter plot.
Again, write down what you think needs improvement and what you measurments you need to do to improve things.
Continue until you are satisfied with your final result.

You need to include uncertainty in these plots and we will show you how to handle that when rescaling graph axes.

Once you are satisfied with the data, and are satisfied with your semilog plot, write down the model that describes intensity versus number of sheets.


Marking Scheme

2 marks for worked examples at the start

2 marks for description of experimental technique, for your first measurements

2 marks for critique of first data and plan for more data-taking

2 marks for critiqe after your second set of data and plan for more data-taking

3 marks for total, final data set with uncertainty
2 marks for semi-log plot of data
2 marks for conclusion, including estimate of the coefficient in the exponential (what model describes the data, including estamates of the coefficients)