A glass lined reactor $12m$ in diameter is situated in a room maintained at $16C.$ The glass lining is $12\mathrm{.}5mm$ thick and the steel shell of the vessel is $10mm$ thick.

If the resistance of the air film on the outside of the reactor is equal to the combined resistances of the glass and steel layers, calculate the temperatures of the glass$-$steel and steel$-$air interfaces when the temperature of the glass surface adjacent to the

reactor contents is $46C.$

Thermal conductivity of steel:

Thermal conductivity of glass:

$70\frac{W}{m}k$

$0\mathrm{.}8\frac{W}{m}k$