Number of photons emitted from a light bulb entering the eye

[dymondahlis]

Homework Statement

A 100W bulb emits light of a single wavelength 6000*10^-10 m. If light spreads out uniformly in space, how many photons enter your eye per second if you are at a distance 1m from the bulb and the pupil diameter is about 1mm?

Homework Equations

E = hc/lambda

The Attempt at a Solution

I found the energy of each photon using E =hc/lambda and i know i have to divide the proportion of light entering the eye by this to find the number of photons entering the eye. I also know that the proportion of light entering the eye is area of pupil/ area of sphere. the area of sphere is 4*pi*r^2 = 4*pi*1 but what is the area of the pupil?

 

[diazona]

The pupil is a circle. What's the formula for area of a circle?

 

[dymondahlis]

pi*r^2
i assumed it would've been harder to find.
thanks so much!