Question

A body is cooling from 80°C to 60°C in a room at 30°C. Compared to the time taken to cool from 60°C to 40°C, the time taken to cool from 80°C to 60°C will be ______.

Options

• More, because the temperature difference is larger

• Less, because the temperature difference is larger

• Equal, because the total drop is the same (20°C)

• Cannot be determined without knowing the mass of the body

Answer 1

A body is cooling from 80°C to 60°C in a room at 30°C. Compared to the time taken to cool from 60°C to 40°C, the time taken to cool from 80°C to 60°C will be less, because the temperature difference is larger.

Explanation:

According to Newton's Law of Cooling, the rate of cooling is directly proportional to the temperature difference (T − T₀). When cooling from 80°C to 60°C, the average temperature difference from surroundings (30°C) is greater, so the body cools faster and takes less time compared to cooling from 60°C to 40°C.