If hot water takes 10 minutes to cool from 90°C to 80°C, then the time taken to cool from 80°C to 70°C is
The time taken for the hot water to cool from 80°C to 70°C will be more than 10 minutes. As the temperature difference decreases, the rate of cooling also decreases according to Newton’s law of cooling. Therefore, it will take more than 10 minutes to cool through this 10°C interval.
Share
The time taken for the hot water to cool from 80°C to 70°C will be more than 10 minutes. According to Newton’s law of cooling, the rate of cooling is proportional to the temperature difference between the body and its surroundings. As the temperature difference decreases, the rate of cooling also decreases.
In the given scenario, the water cools from 90°C to 80°C in 10 minutes. This means the average temperature during this interval is 85°C, which is 60°C above the surrounding temperature. When the water cools from 80°C to 70°C, the average temperature is 75°C, which is 50°C above the surroundings. Since the temperature difference is lower, the rate of cooling will be slower, and it will take more than 10 minutes for the water to cool through this 10°C interval.
Therefore, the correct answer is [C] More than 10 minutes.