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**current**from the detector on an ammeter against the horizontal displacement. Now I must be going crazy because I spoke to a demonstrator in the lab and she said I can just plot this current because current and intensity are proportional. Indeed I proceeded to plot the data and the measurements fitted the predicted values. However I checked and current is not proportional to intensity, it is proportional to the square root of the intensity which mucks everything up. Can anyone think what I have missed.

## Homework Equations

P=I[itex]^{2}[/itex]R

and I=[itex]\frac{P}{A}[/itex]

so I[itex]^{2}[/itex][itex]\propto[/itex]Intensity

## The Attempt at a Solution

The plot comes out as a Gaussian distribution so I=I[itex]_{0}[/itex]e[itex]^{\frac{x}{w_{0}}}[/itex]

w is the beam width, I is intensity and, x is the horizontal position.

So if the current were proportional to the square root of intensity we wouldn't get this distribution.

Thanks in advance to anyone that can help.