Physics

Problem

A tungsten filament behaves approximately as a blackbody with an emitting surface area of

1.2\times10^{-5}\,\text{m}^{2}

and is held at a steady temperature of

2.5\times10^{3}\,\text{K}

for

120\,\text{s}

. Using

\sigma = 5.67\times10^{-8}\,\text{W}\,\text{m}^{-2}\,\text{K}^{-4}

, determine the total thermal energy emitted by the filament during this time. a)

2.0\times10^{3}\,\text{J}

6.4\times10^{3}\,\text{J}

3.2\times10^{3}\,\text{J}

3.2\times10^{4}\,\text{J}