$1-15$ Consider a $150-W$ incandescent lamp. The filament of the lamp is $5-cm$ long and has a diameter of $0\mathrm{.}5$ mm $.$ The diameter of the glass bulb of the lamp is $8$ cm $.$ Determine the heat flux, in $\frac{W}{m^2},(a)$ on the surface of the filament and $(b)$ on the surface of the glass bulb, and $($c$)$ calculate how much it will cost per year to keep that lamp on for eight hours a day every day if the unit cost of electricity is $$\frac{0\mathrm{.}08}{k}Wh.$

FIGURE P$1-15$