A scientist working near an improperly shielded y-ray source would receive an equivalent dose of 4.0 mSv in a 1 hour period. What thickness of lead shieldin is required so that the scientist could work the same distance from the source for s period of 1 hour and only receive an equivalent dose of 0.2 mSv? The linear attenuation coefficient of lead for these y rays is 3.0 cm.

A scientist working near an improperly shielded y-ray source would receive an equivalent dose of 4.0 mSv in a 1 hour period. What thickness of lead shieldin is required so that the scientist could work the same distance from the source for s period of 1 hour and only receive an equivalent dose of 0.2 mSv? The linear attenuation coefficient of lead for these y rays is 3.0 cm.