Pounds
If you are talking about the unit of measurement for weight is that of force it would be Newtons.
The answer to your question is aluminum.
I think the correct answer is light energy. It is light energy that is transformed into chemical energy by plants by the process called photosynthesis. In this process, plants<span> take in water, carbon dioxide, and sunlight and </span>turn<span> them </span>into<span> glucose and oxygen.</span>
It really depends on what the bulb is being used for, since efficiency means how much of the output is USEFUL.
If the bulb is being used for light in a dark room, then it produces (8.2% x 21W) = 1.72 joules per second of light energy.
If the bulb is being used to keep a hamster cage or a fish tank warm, then the 8.2% is the useful part, and the light is the other (91.8% x 21W) = 19.28 joules per second.
A) 2250 meters from starting pont
b) 90 degrees to the right
