Steam at $325C$ flows in a cast iron pipe whose inner and outer diameters are $5$ and $5\mathrm{.}5$ cm $,$ respectively. The pipe is covered with $3\mathrm{.}2$ cm thick glass wool $($Glass fibre duct liner$)$ insulation and is $1$ m long. Heat is lost to the surroundings at $15C$ by natural convection and radiation, with a combined heat transfer coefficient of $19\frac{W}{m^2}K.$

a$)$

Taking the heat transfer coefficient inside the pipe to be $54\frac{W}{m^2}K,$ determine the rate of heat loss from the steam per unit length of the pipe $(\frac{W}{m}).$

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B$)$ Determ$$ne tempature drop across the cast iron pipe Celvius

C$)$ Determine the tempature drop across the insulation Celcius