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Q1 (NDA-I/2008) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Thermal physics Answer Verified

Why do two ice blocks join to form one block when pressed together?

Result
Your answer: —  Â·  Correct: A
Explanation

When two ice blocks are pressed together, the application of pressure lowers the melting point of the ice at the contact interface [1][t1]. This phenomenon, known as regelation, causes a thin layer of ice to melt into water even if the ambient temperature is below 0°C [t2][t4]. Unlike most solids where pressure increases the melting point, ice is an exception because water is denser than ice [c1][t6]. Once the pressure is released, the melting point returns to its normal value (0°C), and the thin layer of water refreezes [t2][t4]. This refreezing (solidification) acts as a bond, causing the two separate blocks to fuse into a single block [t1][t4]. This principle also explains why ice balls can be formed by squeezing shredded ice and how glaciers slide over terrain [t4][t9].

Sources

  1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > UPSC Prelims 2009] In the structure of planet Earth, below the mantle, the core is mainly made up of which one of the following? > p. 56
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SIMILAR QUESTIONS

CDS-I · 2002 · Q50 Relevance score: 2.61

When two icecubes are pressed together, they join to form one cube. Which one of the following helps to hold them together?

NDA-II · 2010 · Q99 Relevance score: 1.95

Two identical blocks of ice, Aand B, float in water as shown in the figure given below. Which one among the following statements in this regard is correct?

CDS-I · 2006 · Q49 Relevance score: 0.65

Assertion (A): It is possible to fuse two ice cubes by pressing them together. Reason (R): Pressure affects the melting point of a solid

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Strips of two metals A and B are firmly joined together as shown in the figure(Before Heating) On heating, A expands more than B does. If this joined strip is heated, then it will appear as

NDA-I · 2009 · Q23 Relevance score: -3.65

Assertion (A) : In summer a block of iron is hotter than a block of wood. Reason (R) : The relative density of iron is more than the relative densi ty of wood