The Tungsten Filament Inside a Light Bulb Is Heated to a Temperature

question 42

Multiple Choice

The tungsten filament inside a light bulb is heated to a temperature of 1250 K.It has a surface area 2 cm².What is the net power radiated by the light bulb at room temperature (25 ^$\circ$ C) ? (emissivity of tungsten is 0.7)

• A)3 W
• B)12 W
• C)19 W
• D)52 W
• E)100 W

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