A camera lens has a focal length of 180.0 mm and an aperture diameter of 16.36 mm. (a) What is the ƒ-number of the lens?

Video transcript

Hi everyone. In this practice problem, we're being asked to determine the F number of a photographic system having an aperture diameter of 10.5 centimeter and a focal length of centimeter. The options given for the F numbers are a eight B 75 C 893 and D cannot be determined from the given information. So the F number of a photographic system is defined as the focal length of the lens divided by the diameter of the aperture of the lens. So F number essentially we have the equation or can be calculated by F number equals to focal length defined it by the aperture diameter I for sure diameter just like. So, so we can immediately just substitute those information from the problem statement. So that F number will then be equals to focal length is given to be centimeter. And then the aperture diameter is given to be 10.5 centimeter. And doing this calculation, we will then get our F F number value to then be equal to eight. So the F number of this photographic system is going to be equal to eight which will correspond to option A in our answer choices. So option A will be the answer to this particular practice problem and that'll be it for this video. If you guys still have any sort of confusion, please feel free to make sure to check out our adolescent videos on similar topics available on our website. But other than that, that will be it for this one. Thank you.