2. An isotropic point source emits 1010 y-rays/sec with an energy of 1 MeV. The source is surrounded by a lead shield 10 cm thick. Calculate at the surface of the shield: 1. the flux in the absence of the shield 2. the uncollided flux 3. the buildup flux 4. in the absence of the shield 5. without the buildup of scattered radiation 6. with buildup