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Question about Uncertainties?


mariemarie

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This is for a bio lab.

But anyway,

How would one calculate an uncertainty for light intensity. I am using the formula WATTS/4π(0.1)^2. Where 0.1 is the distance of the light from the object which i measured with a ruler and than converted to meters. So wouldn't my uncertainty for my ruler be +/- 0.5cm but what would my uncertainty for my WATTS light bulb be and for my light intensity in total??? I am really confused, any help will be greatly appreciated!

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I don't know what rulers you use, but don't the standard ones measure millimeters? Your uncertainty tells me that it doesn't. I'll assume you made a mistake there. Your measurement is was originally 10.00+/- 0.05cm, and now it should be 0.1000 +/-0.0005m.

I don't take biology, but your measurement for watts should be dependent on the uncertainty of your reading (how you got the value for watts). Did you use a multimeter? Or was the watt reading already given? If you can give me some information about this, I will probably be able to help you a bit more.

In general when you divide uncertainties, you add their percentage uncertainties.

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