KUSH PATEL

Thomas Edison tried two thousand different materials in search of a filament for
the light bulb. When none worked satisfactorily, his assistant complained,
“All our work is in vain. We have learned nothing.”
Edison replied very confidently, “Oh, we have come a long way and we have
learned a lot. We now know that there are two thousand elements which we
cannot use to make a good light bulb.”
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