A brass boiler has a base area of `0.15 m^2` and thickness 1.0 cm it bolis water at the rate of 6.0 kg/min, when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the bolier. Thermal conductivity of brass ` =609 J s^(-1) .^@C^(-1).` Heat of vaporisation of water ` =2256 xx 10^3 J g^(-1)`