1. What would be the exposure irradiance (mj/cm2) in the beam of a laser pointer for a duration of 0.25 seconds if the laser has a power output of 10 mW and an aperture of 5 mm? Assume there is no significant beam divergence or atmospheric attenuation over the distance the beam travels.

If this is a crystal diode laser producing green light at a wavelength of 532 nm, would the irradiance be in compliance with the TLV for direct intrabeam ocular exposure?

2. A microwave antenna has a power output of 5700 watts and a gain of 5000. Calculate the required decibels of attenuation for a shield that would reduce the exposure from this antenna to a value equal to the allowable power density (OSHA RPG ) at a distance of 69.8 feet (2128 cm) from the antenna. Assume this point is in the far field. [note: dB attenuation = 10 log (W0 /W)]