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  4. The emissivity and surface area of tungsten filament of an electric bulb are 0.35 and 0.25 × 10-4 metre 2 respectively. The operating temperature of filament is 3000 K. If σ=5.67 × 10-8 watt metre -2 K -4, then power of bulb is approximately:

Q. The emissivity and surface area of tungsten filament of an electric bulb are and respectively. The operating temperature of filament is . If watt metre , then power of bulb is approximately:

Thermal Properties of Matter Report Error

Solution:

Given that




We use


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