3. Investigating the relationships between time, current, and capacity In Lecture 3.1, we looked at how a pacemaker battery using the Li/I2 chemistry has less mass than one with Zn/HgO chemistry on account of the higher specific capacities of lithium and iodine. In Lecture 5.3, we looked at how the time for a battery to completely discharge could be related to its capacity and extent of reaction. These concepts will be combined to look at how the cell capacity and discharge current affect the lifetime of primary batteries in the following problems. (a) How many grams of lithium metal and grams of iodine are needed in a lithium-iodine pacemaker battery for it to last for a 6-year lifetime at a constant current of 30 microamperes? Assume that all of the reactants will be consumed during this time period. Use the theoretical specific capacities from Linden Table 1.1. (b) If you had a Zn/HgO battery in the pacemaker with a total mass of 8 grams, what would its lifetime be (if all reactants are consumed) with a constant current draw of 30 microamperes? Use the theoretical specific capacities from Linden Table 1.1. (c) Determine the kilograms of lithium metal needed for the 10,000 Ah backup storage battery used by the military missile launch facilities we discussed in Lecture 3.1. What is the maximum current that can be drawn if the battery needs to last for 20 years before the lithium is completely consumed? Assume a constant current draw.