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I believe the reason why light bulbs often "burn out" when they are
switched on is that at the instant of being turned on their resistance is
*much* lower than when at operating temperature (for how much lower, see
Brian W.'s posts). This short circuit condition results in a huge initial
current pulse being sent through the filament. The mutual magnetic forces
acting on different parts of the (coiled) filament due to the current pulse
causes a mechanical shock to the filament, flexing it.