Question

Light of intensity 2.00 W/m2 passes through the pupil of one of your eyes and eventually falls on your retina. The radius of the pupil is controlled by the iris. In a human eye, the radius of the pupil can vary from about 1.0 mm to about 3.5 mm. The area of the opening can be calculated from pi (3.1416) times the radius squared. If your pupil is open to a radius of 2.5 mm, how much light energy passes through in one minute

Answer 1

Step-by-step explanation:

Intensity of light, I = 2 W/m²

radius of pupil open, r = 2.5 mm = 2.5 x 10^-3 m

time, t = 1 min = 60 second

Energy passes, E = intensity x area x time

E = 2 x 3.14 x 2.5 x 2.5 x 10^-6 x 60

E = 2.36 x 10^-3 Joule