Hello! I'm having difficulty answering the following question:(adsbygoogle = window.adsbygoogle || []).push({});

Camera A has a lens with an aperture diameter of 8.50 mm. It photographs an object using the correct exposure time of 3.33×10−2 s.

What exposure time should be used with camera B in photographing the same object with the same film if this camera has a lens with an aperture diameter of 22.8 mm?

I have no idea how to approach this problem. It's the only problem of the chapter that deals with time and aperture diamter - the only formula I can use is : f/D (focal lenght/aperture diameter). However I don't understand where time fits in there. I hope someone can help me start this problem. Thank you.

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# Geometric Optics question

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