Physics

Problem

A homeowner wants to limit the steady-state rate of thermal energy loss through a

35\,\text{m}^2

section of wall to no more than

200\,\text{W}

. The indoor air is at

22\,^{\circ}\text{C}

and the outdoor air is at

-3\,^{\circ}\text{C}

. The wall will be filled with fiberglass insulation of thermal conductivity

0.040\,\text{W}\!/\!(\text{m}\cdot\!^{\circ}\text{C})

. Approximately what minimum thickness of insulation is required? a)

14\,\text{cm}

35\,\text{cm}

18\,\text{cm}

7.0\,\text{cm}