If it produces 20J of light energy in a second, then that 20J is the 10% of the supply that becomes useful output.
20 J/s = 10% of Supply
20 J/s = (0.1) x (Supply)
Divide each side by 0.1:
Supply = (20 J/s) / (0.1)
<em>Supply = 200 J/s </em>(200 watts)
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Here's something to think about: What could you do to make the lamp more efficient ? Answer: Use it for a heater !
If you use it for a heater, then the HEAT is the 'useful' part, and the light is the part that you really don't care about. Suddenly ... bada-boom ... the lamp is 90% efficient !
<span>Science is orderly knowledge proven by experimentations.</span>
Unclear/incomplete question. However, I inferred you need an explanation of the phenomenon of rainfall.
<u>Explanation</u>:
Basically, the phenomenon of rainfall follows a natural cycle called the water cycle. What we call <em>'rainfall'</em> occurs when water condensed (in liquid form) in the atmosphere is made to fall down on the ground as tiny droplets as a result of the forces of gravity.
<u>The water cycle makes rainfall possible:</u>
- First, water on the earth's surface is evaporated (or is absorbed into) the atmosphere.
- Next, it then condensed into liquid form; which later falls to the surface to the ground again. And the process continues.
