posted by Jessica .
A computer and monitor use 800J of electric energy each second. The monitor produces 30J of light energy each second. The fan in the computer converts 15J each second into kinetic energy. The lights on the tower give off 10J of light energy. If all the remaining energy is converted into heat, what percentage of the initial electric energy was converted into useful forms (as opposed to heat)?
I will be happy to critique your work.