What is the f-number of a camera lens that has an aperture-opening diameter of 0.30 cm and a focal length of 6.0 cm?
A)0.30
B)1.8
C)20
D)6.0
E)0.05

Question

What is the f-number of a camera lens that has an aperture-opening diameter of 0.30 cm and a focal length of 6.0 cm?
A)0.30
B)1.8
C)20
D)6.0
E)​0.05

Quizplus · Accepted Answer

The f-number is determined by dividing the focal length of the lens by the diameter of the aperture-opening. Therefore, f-number = focal length / aperture diameter = 6.0 cm / 0.30 cm = 20. Therefore, the correct answer is (C) 20.

What Is the F-Number of a Camera Lens That Has