Ice at 273 K would absorb latent heat as well as the heat heat energy in order to attain the room temperature. Water at 273 K would just absorb heat energy in order to attain the room temperature. Thus, the water at 273 K would absorb less amount of heat energy from the surroundings as compared to ice at 273 K. Therefore, ice at 273 K is more effective in cooling then water at the same temperature.
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