The specific latent heat of fusion of ice is 336 kJ/kg. The heat required to melt 2 kg of ice at 0°C is:
A. 1344 kJ
B. 672 kJ
C. 168 kJ
D. 336 kJ
Answer: Option B
Solution (By JKExamLibrary)
Heat for phase change Q = m·L_f, where L_f is latent heat of fusion. Thus Q = 2 kg × 336 kJ/kg = 672 kJ. This direct application tests calorimetry fundamentals. Memory aid: 'Latent heat: Q = mL; no temperature change during phase transition'. Competitive exams frequently test such calculations with standard values. Always ensure units match (kg and kJ/kg here); convert if necessary. This problem assesses basic formula application skills essential for thermodynamics sections.
Explanation:
Water has a specific heat capacity of 4184 J/kg·K, which is very high. This means it heats up and cools down much more slowly than land. During the day, land heats faster than the sea, causing air above it to rise and cool air from the sea to rush in (sea breeze). The reverse happens at night (land breeze).
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