Tungsten filament incandescent bulbs trains is in a state of tense tempeaturu 2300 ° C. What density j and current I, flowing through the filament, if diamert 20 microns, length of 0.5 m, and the voltage on the filament 200? Specific tungsten resistance at 0 ° C is equal to 5.5 x 10 -8 ohm * m, temperature coefficient of resistance of 4.6 x 10 -3 K -1 ^.

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