The concrete slab of a basement is 11 m long, 8 m wide, and 0.20m thick. during the winter, temperatures are nominally 17 C and 10 C at the top and bottom surfaces respectively. if the concrete has a thermal conductivity of 1.4 W/mK what is the rate of heat loss through the slab? if the basement is heated by a gas furnace operating at an efficiency of n=0.9 and natural gas is priced at C=$0.02/MJ, what is the daily cost of the heat loss?