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. 336 kJ
C. 168 kJ
D. 672 kJ
Answer: Option D
Solution (By JKSSB Mock Tests)
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.
The amount of heat required to change the state of 1 kg of a substance from solid to liquid at its melting point without any change in temperature is called:
Explanation:
The heat required to change a solid into a liquid at its melting point without a temperature rise is called the Latent Heat of Fusion. The word 'latent' means hidden, because this heat energy breaks intermolecular bonds to change the phase rather than increasing the kinetic energy (temperature) of the molecules.
Explanation:
At highest point velocity is zero, but acceleration due to gravity is still g (9.8 m/s²) downward. This causes it to fall back. Acceleration constant throughout free fall.
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