20 x 20 x 50 cm: glass, iron, aluminium, ceramic.
A LED torch sheds light on an incandescent light bulb
The light bulb was invented in 1802, and optimized for commercial use by Edison in 1878. The light bulb is still for sale in 2017. It is possibly the longest lasting technology in modern times.
The LED was invented in the 1990ies, and gives the same amount of light as a modern light bulb, consuming about one tenth of the energy.
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