A window pane that measures $20$ cm x $25$ cm is set into the front

of a house. The glass is $0\mathrm{.}32$ cm thick. The temperature outside is

$-15$ degree C and inside is $22$ degree C$.$ At what rate does heat

leave the house through that one small window.

$($thermal conductivity of glass K $=0\mathrm{.}63$ W$/$mK$)$

$2.$ If single pane window is replaced by a double pane window with

air gap of $0\mathrm{.}5$ cm between the panes. The inner surface of inner

pane is $22$ degree C and outer surface of outer pane is $-15$ degree

C$.$ What is new heat loss through double pane window.

$($thermal conductivity of air is K $=0\mathrm{.}023$ W$/$mK$,$ for glass K$=0\mathrm{.}63$ W$/$mK$)$