The given graph represents the cooling curve of a liquid.
(a) State the freezing temperature of the liquid.
(b) Name the phase change happening at the region QR.
(c) In which state (solid / liquid) does the above substance liberate heat at a faster rate? Justify.
(a) The freezing temperature is 20°C because the graph becomes horizontal at this temperature.
(b) The phase change in region QR is freezing, where the liquid changes into solid.
(c) The substance liberates heat faster in the solid state. The graph after point R has a steeper slope, indicating a faster decrease in temperature than in the liquid state before point Q.
More ICSE Moderate level questions
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