Answer
(a) i. The overall efficiency is 7%
ii. 0.07 kg is converted into fluorescent light.
iii. The system's efficiency could be improved if there was a way to directly convert the energy to fluorescent light in fewer steps. This would work because according to the second law of thermodynamics, each time there is a conversion of energy, the ability to do work is decreased.
(b) The first law of thermodynamics is that energy cannot be created or destroyed. The second law of thermodynamics is that energy loses some of its ability to do work each time it is converted.
(c) 7040000000 years
Work Step by Step
(a) .35*.90*.22= .07
ii. .07*1=.07
iii. See the second law of thermodynamics.
(b) First and second laws of thermodynamics.
(c) The half life is 704 million years. 704 million times the 10 half lives gives that it would take 704000000 years.
