Precious metals. You have developed an environmental conscience. You have also met the girl of your dreams whom you are about to marry. The wedding ring you would like to buy for her is 24 carat...

Precious metals. You have developed an environmental conscience. You have also met the girl of your dreams whom you are about to marry. The wedding ring you would like to buy for her is 24 carat (100%) gold and weighs 10 grams. She prefers one made of a 5050 platinum-rhodium alloy weighing 15 grams. How different are the embodied energies of the two rings? (Table 6.2 has data for precious metals.)

Since this is a silly question already, we’ll add the light bulb test. With a conversion efficiency of 0.38 for primary energy to electrical energy, for how many extra hours could you run a 100-watt bulb if your girlfriend is willing to settle for the gold ring? (Remember 1 kWh 5 3.6 MJ.)