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A container si filled up to its brim with water with a piece of ice floating on it [Fig 5.15(a)]. State the effect on the level of water in it container when ice melts completely, if the initial temperature of water was (i) 0^(@)C (ii) 4^(@)C and (iii) above 4^(@)C. |
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Answer» Solution :VOLUME expansion of the container at the temperatures mentioned is neglected. (i) There will be no change in the water level. Here mass of ice is equal to the mass of the displaced water as per the condition of floatation. Ice, being at `0^(@)C`, produces water at `0^(@)C` on melting. Volume of that water is equal to the space formerly occupied by the immersed portion of ice. Hence, water THUS formed on melting of ice exactly fills the space [Fig.5.15(b)].  (II) Some water will OVERFLOW from this container. Density of water is maximum at `4^(@)C`, so water formed on melting of ice at `0^(@)C` is of lower density. Therefore the volume of this water will be greater than the volume of water displaced by floating ice at `4^(@)C` [Fig 5.15(c)]. (iii) The water level will come down [Fig.5.15(d)]. Mass of the ice floating is equal to the mass of water displaced by the ice. According to the question, temperature of the water is above `4^(@)C`. Receiving heat from the surroudings and water, the ice produces water at `0^(@)C` on melting. Density of water at `0^(@)C` is higher than that of water at `4^(@)C`.Hence, volume of the water displaced is more than the volume of the water produced on melting. Also, temperature of the water falls as it supplies heat to the ice. With decrease in temperature, volume of the water also DECREASES. |
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