A brass boiler has a base area of 0.15m^(2) and thickness 1 cm. Water boils in it at the rate of 6.0 kg/min, when placed on flame. Estimate the temperature of the part of the flame in contact with the boiler. Thermal conductivity of brass = 109 J/sm-K and latent heat of vapourisation of water = 2256 J/g.

A brass boiler has a base area of 0.15m^(2) and thickness 1 cm. Water

1.	A brass boiler has a base area of 0.15m^(2) and thickness 1 cm. Water boils in it at the rate of 6.0 kg/min, when placed on flame. Estimate the temperature of the part of the flame in contact with the boiler. Thermal conductivity of brass = 109 J/sm-K and latent heat of vapourisation of water = 2256 J/g.
Answer» Solution :Let `T_(1)` be the temperature of the part of the flame in contact with BOILER. The amount of heat flown into water in 1 MINUTE `Q=(KA(theta_(1)-theta_(2))t)/L=(109xx0.15xx(T_(1)-100)xx60)/0.01` Mass of water boiled in 1 minute = 6KG = 6000g. Heat required to boil the water, Q = mL = `6000xx2256` `therefore(109xx0.15xx(T_(1)-100)xx60)/0.01=6000xx2256` (or) `T_(1)-100=138""thereforeT_(1)=238^(@)C`