1. The problem statement, all variables and given/known data I have done the light ray through a glass block experiment at different angles. I've taken the measurement for i1 which is from the incident ray. and i2 which is from the emergent ray. Then I have to take the average of i1 and i2 and then plot a graph using the average value. I have to of course do this for various incident angles and their corresponding emergent angles. So it'll be a sin i over sin r graph. However, if I measure an incident angle i1 to be 15 degrees and the corresponding i2 emergent to be 16, then that means the average will be 15.5 degrees. I have to plot the graph using average values. However the protractor only measures to an accuracy of 1 degree, so would I be correct in plotting using the value for sin16 as opposed to plotting for sin15.5 ? Thanks!