Question (1): The measured effective irradiance at a distance of 10 cm from the centre of a UV lamp is 2.4 mW/cm². Assuming the radiation to be isotropic, calculate (a) the irradiance at a distance of 50 cm, and (b) the limiting exposure time at this irradiance. Question (2)(a): A Q-switched ruby laser, |=694.3 nm, emits 15 J/pulse. If a pulse of this radiation, in a beam 1.6 cm in diameter, were accidentally to fall on an eye whose iris was opened to 7 mm diameter, and the focal length of the lens is 1.7 cm calculate the radiant exposure at (a) the cornea and (b) the retina. (c) If the aperture diameter of the laser is 1.3 cm, what is the emergent radiant exposure per pulse? Question (2)(b): If the MPE() for direct ocular exposure, intrabeam viewing, for this ruby laser is, where is the exposure time and the pulse length is, how do the radiant exposures calculated for the cornea and retina compare to the MPE?