UPSC CDS 2 2022 GK Paper

Concept:Water shows anomalous expansion: from $0^\circ\text{C}$ to $4^\circ\text{C}$, its density increases, reaching a maximum at $4^\circ\text{C}$.Explanation:When water is heated from $0^\circ\text{C}$ to $4^\circ\text{C}$, its density increases.At $0^\circ\text{C}$, water contains ice-like clusters that keep molecules farther apart, giving a lower density.As temperature rises to $4^\circ\text{C}$, these clusters break, molecules move closer together, and density increases.At $4^\circ\text{C}$, water reaches its maximum density of $1000\ \text{kg m}^{-3}$.After $4^\circ\text{C}$, further heating causes molecules to move faster and spread apart, decreasing density.Thus, for the specific range $0^\circ\text{C}$ to $4^\circ\text{C}$, density only increases.The options include "first increases then decreases" but that applies only if heating continues beyond $4^\circ\text{C}$.Within the given range, the density simply increases.Answer:B. increases.