One end of a uniform brass rod 20 cm long and 10 cm2 cross-sectional area is kept at 100∘C . The other end is in perfect thermal contact with another rod of identical cross-section and length 10 cm. The free end of this rod is kept in melting ice and when the steady state has been reached, it is found that 360 g of ice melts per hour. Calculate the thermal conductivity of the rod, given that the thermal conductivity of brass is 0.25 cal/s cm∘C and L=80 cal/g .