Initially, a beaker has 100 g of water at temperature 90 ° C . Later another 600 g of water at temperature 20 ° C was poured into the beaker. The temperature, T of the water (in ° C ) after mixing is

Step-by-step solution

Given, Mass of water at 90 o   C = 100   g = 100 × 10 - 3   kg Mass of water at 20   ° C = 600   g = 600 × 10 - 3   kg From calorimetry 100 × 10 − 3 S w ( 90   ° C − T   ° C ) = 600 × 10 − 3 S w ( T   ° C − 20   ° C ) 90 − T = 6 T − 120 T = 210 7 = 30   ° C