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How much mechanical work must be done to completely melt 1 gram of ice at 0°C ?
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- 4.2 J
- 80 J
- 336 J
- 2268 J
- 4.2 J
Correct Option: B
When water at 0 degree Celsius freezes, each gram of water gives off 80 calories. The temperature of the water stays at 0 degree C until every drop has frozen. When ice at 0 degree Celsius melts, it absorbs an equal amount of heat—80 calories for each gram of ice—and its temperature remains unchanged until it has completely melted.
