The filament in a light bulb has a diameter of 0.050 mm and an emissivity e = 1.0. The temperature of the filament is 3000°C. How long should the filament be in order to radiate 60 W of power?

The Stefan-Boltzmann constant is 5.67 × 10-8 W/(m2?K4).
A)

11 cm

B)

9.4 cm

C)

8.6 cm

D)

7.2 cm

E)

5.9 cm


E

Physics & Space Science

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