A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The...

\mathrm{L}=10 \mathrm{~cm}, \mathrm{~d}=0.5 \mathrm{~mm}, \mathrm{~T}=1727^{\circ} \mathrm{C}=2000 \mathrm{~K}$<br/>Power,$\mathrm{P}=94.2 \mathrm{~W}$<br/>$\mathrm{P}=\varepsilon \sigma \mathrm{AT}^4$<br/>$94.2=\varepsilon \times\left(6 \times 10^{-8}\right)(\pi \mathrm{dL})(2000)^4$<br/>$94.2=\varepsilon \times\left(6 \times 10^{-8}\right)(3.14)(0.5)\left(10^{-3}\right)$<br/>\left(10 \times 10^{-2}\right)(2000)^4$
$\varepsilon=\frac{94.2}{(94.2)(16)}=\frac{5}{8}$