Medical Problem from Intro to Health Physics by Cember and Johnson

[xyz_physics]

Hello guys, can you please help me figure out how to solve this problem. Many thanks!

A scanning He–Ne laser that scans at a rate of 10 s−1 emits 5 mW through an
aperture of 0.7 cm. If the beam divergence is 5 milliradian, then, for an intrabeamviewing
distance of 200 cm, calculate
(a) the time during each scan that the pupil of the eye can be exposed,
(b) the radiant exposure per scan,
(c) the average irradiance at the cornea, and
(d) the hazard class that should be assigned to this laser?

 

[Monique]

You should post your question in the https://www.physicsforums.com/forumdisplay.php?f=152" and follow the guidelines that are listed when you post the new thread.