1- A 1.8 mW helium-neon laser beam delivers a spot of light 8 mm in diameter across a room 17 m wide. The beam radiates from a small circular area of diameter 0.5 mm at the output mirror of the laser. Assume irradiance is constant across the diverging beam. What is the radiance (in SI units) of the laser? Give your answer to 3 significant figures.
2- A small monochromatic light source, radiating at 455 nm, is rated at 992 W. If the source radiates uniformly in all directions, determine its radiant intensity in SI units. Give your answer to 1 decimal place.