An owl has good night vision because its eyes can detect a light intensity as small as 5.0 × 10^-13 W/m^2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 8.1 mm and the light has a wavelength of 511 nm?
Added by Noelia B.
Step 1
The pupil is circular, so we use the formula for the area of a circle, which is πr^2. The radius is half the diameter, so r = 8.1 mm / 2 = 4.05 mm = 4.05 x 10^-3 m. Area = π(4.05 x 10^-3 m)^2 = 5.15 x 10^-5 m^2. Show more…
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An owl has good night vision because its eyes can detect a light intensity as small as 5.0 × 10-13 W/m2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 8.1 mm and the light has a wavelength of 535 nm?
Sufiyan A.
An owl has good night vision because its eyes can detect a light intensity as small as 5.0 10-13 W/m2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 8.5 mm and the light has a wavelength of 500 nm?
Penny R.
Owl Vision Owls have large, sensitive eyes for good night vision. Typically, the pupil of an owl's eye can have a diameter of $8.5 \mathrm{mm}$ (as compared with a maximum diameter of about $7.0 \mathrm{mm}$ for humans). In addition, an owl's eye is about 100 times more sensitive to light of low intensity than a human eye, allowing owls to detect light with an intensity as small as $5.0 \times 10^{-13} \mathrm{W} / \mathrm{m}^{2} .$ Find the minimum number of photons per second an owl can detect, assuming a frequency of $7.0 \times 10^{14} \mathrm{Hz}$ for the light.
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