We had an experiment of charging and dicharging a capacitor in a RC circuit.Our instructor asked us to plot our data in a semilogarithmic paper.Then told us the formula of calculting the slope of such a curve.It was:(adsbygoogle = window.adsbygoogle || []).push({});

[itex] \frac {[the vertical distance between two points measured by a ruler]*2.3}{the distance of two successive ones]*[the difference of the two ponit's independent variables]}[/itex]

then asked us two prove that what is this slope I did the following:

[itex]\frac{log \frac{i_{2}}{i_{1}} *ln{10}}{\Delta t}=\frac{ln{i_{2}}ln{i_{1}}}{\Delta t}[/itex]

And we have [itex] ln{i} = ln{\frac{\Epsilon}{R}}-\frac{t}{RC}[/itex]

So we get that the slope is -1/RC.

But the instructor says this proof is incomplete.What's the problem?Can you tell what quantity does this slope idicate?

thanks

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# Slope of a semilog plot

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