1. You are conducting an experiment on fluorescent proteins populating a 1-dimensional channel with length L=200m. With the ultra-fast pulse of a laser that has a 1m spot size, you excite the channel at L/2. Each pulse excites 108 proteins that subsequently begin to diffuse away. For this protein, D = 25/(4p) m2 /sec

A. What is the concentration of particles within the illuminated 1m location 5s after the excitation?

B. What is the concentration of particles at location L/4 at that time?

C. What would be the concentration of particles at L/4 at that time if the 1m pulse illuminated molecules at 3L/4 (instead of at L/2)?