I believe the answer you are looking for is an exergonic reaction; it explains that some form of energy (light) is given of by the chemical reactions which make it glow.
pie
the sun maintain its energy output by nucler fusion
Input energy = output energy + losses
Watts is energy output. Watts is joules per second. Joules is energy.
You divide useful output energy by the input energy. Or equivalently, useful output power by input power.
The reaction that makes a firefly glow in terms of energy is referred to as exergonic. This would be an output.
It is the opposite of an exergonic reaction. An energonic reaction would be one where more energy is put into the reaction than what comes out of it (like endothermic), while exergonic has more output energy than input (like exothermic).
The energy input is always greater than energy output.
the sun maintain its energy output by nucler fusion
pie
Input energy = output energy + losses
Energy output refers to the amount of usable energy obtained from a system, while energy input is the amount of energy required to operate that system. A system is considered efficient when the energy output is greater than the energy input. Conversely, inefficiency occurs when more energy is put into a system than what is obtained as output.
The result (ratio) of such a comparison is called the efficiency. Note that total energy output must be equal to energy input (conservation of energy); however, what is relevant for this comparison is the useful energy output.
Watts is energy output. Watts is joules per second. Joules is energy.
You divide useful output energy by the input energy. Or equivalently, useful output power by input power.
Efficiency = ( useful energy output / total energy input ) x 100
energy