An incandescent light bulb has a tungsten filament that is heated to a temperature $3 \times 10^{3} K$ when an electric current passes through it. If the surface area of the filament is approximately $10^{- 4} m^{2}$ and it has an emissivity of $0.32$ , the power radiated by the bulb is

147 W

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175 W

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200 W

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225 W

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Solution

The correct option is A $147 W$
Given,
$T = 3 \times 10^{3} K$
$A = 10^{- 4} m^{2}$
$e = 0.32$
$σ = 5.67 \times 10^{- 8} W m^{- 2} K^{- 4}$
Power radiated by the bulb ,
$P = e A σ T^{4}$
$P = 0.32 \times 10^{- 4} \times 5.67 \times 10^{- 8} (3000)^{4}$
$P = 147 W$

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An incandescent light bulb has a tungsten filament that is heated to a temperature 3×103 K when an electric current passes through it. If the surface area of the filament is approximately 10−4 m2 and it has an emissivity of 0.32, the power radiated by the bulb is

The correct option is A 147 WGiven,T=3×103KA=10−4m2e=0.32σ=5.67×10−8Wm−2K−4Power radiated by the bulb ,P=eAσT4P=0.32×10−4×5.67×10−8(3000)4P=147W

An incandescent light bulb has a tungsten filament that is heated to a temperature $3 \times 10^{3} K$ when an electric current passes through it. If the surface area of the filament is approximately $10^{- 4} m^{2}$ and it has an emissivity of $0.32$ , the power radiated by the bulb is

The correct option is A $147 W$
Given,
$T = 3 \times 10^{3} K$
$A = 10^{- 4} m^{2}$
$e = 0.32$
$σ = 5.67 \times 10^{- 8} W m^{- 2} K^{- 4}$
Power radiated by the bulb ,
$P = e A σ T^{4}$
$P = 0.32 \times 10^{- 4} \times 5.67 \times 10^{- 8} (3000)^{4}$
$P = 147 W$