Problem one:

A glass window of width $W=1m$ and height $H=2m$ is $5$ mm thick and

has a thermal conductivity of $k_g=1\mathrm{.}4\frac{W}{m}.K.$ If the inner and outer

surface temperatures of the glass are $15C$ and $20C,$ respectively, on a

cold winter day, what is the rate of heat loss through the glass? To reduce

heat loss through windows, it is customary to use a double pane

construction in which adjoining panes are separated by an air space. If

the spacing is $10$ mm and the glass surfaces in contact with the air have

temperatures of $10C$ and $15C,$ what is the rate of heat loss from $1$ mx $2$ m

window? The thermal conductivity of air is $k_a=0\mathrm{.}024\frac{W}{m}.K.$