A copper ball of mass 100 gm is at a temperature T. It is dropped in a copper calorimeter of mass 100 gm,
filled with 170 gm of water at room temperature. Subsequently, the temperature of the system is found to
be 75
o
C. T is given by: (Given : room temperature = 30
o
C, specific heat of copper = 0.1 cal/gm
o
C)