(a) What is the average absorbed dose in a 50-cm' region of a body organ (density = 0.93 g/cm') that absorbs 2 x 10$ MeV of energy from a radiation field? (b) If the energy of (a) is deposited by ionizing particles with an LET of 15 keV/um in water, what is the dose equivalent? (use the value or equation in the lecture note, which you need for calcuation)