Question

3. A state-of-the-art iPhone features a battery of ca. 3000 mAh capacity. The battery features an open circuit voltage of 3.7 V. Given that power=voltage ́current. And assume that each fully charged battery lasts 2 days of normal usage. How many days of usage can we sustain if we could transfer all energy we consume a day to power an iPhone?

4. Ampere (A) is the unit used to measure the flow of electricity. 1A equals the amount of electricity delivered by 6.2´1018 electrons past a point in 1 second. In a hydrogen fuel cell, hydrogen atoms are dissociated into H+ ions and electrons (HàH+ + 1e- ). How many grams of hydrogen must be dissociated each second in a fuel cell to produce 1 A of electricity? How many grams are needed to fully charge an iPhone (use information from Problem #3 above)?

Answer 1