Translations:AY Honors/Optics/Answer Key/47/en
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[math]\displaystyle{ f_2 }[/math] should come out as a negative number.
Another method for measuring focal length of a negative lens:
![](/images/thumb/6/62/MeasuringNegativeLensFocalLenght.png/450px-MeasuringNegativeLensFocalLenght.png)
Measuring the focal length of a negative lens using measuring microscope. Link->[1]