Question #39882

The focal length of the human eye is approximately 1.7cm.

Part A

What is thef-number for the human eye in bright light, when the pupil diameter is2.5mm?

f_{\rm number}= __________

Part B

What is thef-number in dim light, when the pupil diameter has expanded to7.0mm?

f_{\rm number}= __________

Express your answers using two significant figures.

Part A

What is thef-number for the human eye in bright light, when the pupil diameter is2.5mm?

f_{\rm number}= __________

Part B

What is thef-number in dim light, when the pupil diameter has expanded to7.0mm?

f_{\rm number}= __________

Express your answers using two significant figures.

Expert's answer

In the case of the human eye, the pupil diameter is the optical aperture. The f number is determined as f = focal length / aperture. For case A this means f = 17 mm / 2.5 mm = 6.8 For case B this means f = 17 mm / 7 mm = 2.4&

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