[填空题]
A 100-W lightbulb ha*iodzic/. 8, p mv50 otthsc*xs a ru3,i03puox+hbxvv ,lx -c-lg esistance of about $12\Omega$ when cold ($20^{\circ}\,C$) and $140\Omega$ when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity $\alpha\,=\,0.0060(C?)^{-1}$ . $^{\circ}\,C$
