A solid aluminium sphere at 550°C is quenched in a 40°C water bath, cooling to 450°C in 20 seconds. What is the approximate expected temperature of the ball after another 20 seconds ____________________ °C?
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Answer: A. 370
Explanation
As the temperature difference between the aluminum sphere and water bath decreases, the rate of cooling slows exponentially. Applying transient heat conduction principles shows that temperature drops diminish in magnitude during each successive time interval. Calculating this cooling curve predicts that the ball temperature will drop to approximately 370 degrees Celsius. Thermal quenching involves rapidly immersing hot metal objects into liquid baths to alter their material properties. Newton law of cooling states that the rate of heat loss is proportional to the temperature difference. Transient heat transfer analyzes how object temperatures change over time when subjected to changing thermal environments.
Option b assumes a linear cooling rate that fails to account for exponential decay in temperature differentials. Option c underestimates the remaining thermal energy by assuming excessive temperature drops during later intervals. Option d suggests an unrealistic cooling velocity that contradicts transient heat transfer mathematical principles.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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