A calorimeter of mass m contains an equal mass of water in it. The temperature of the water and calorimeter is t2>0∘C. A block of ice of mass m and temperature t3<0∘C is gently dropped into the calorimeter. Let C1,C2 andC3 be the specific heats of material of calorimeter, water and ice respectively and L be the Latent heat of ice. The whole mixture in the calorimeter becomes ice if