When does the flow of heat from a hot object to a cold object stop ?

Answer

**Step-by-Step Solution:**

1. **Understanding Heat Flow**: Heat flows from a hot object to a cold object due to the difference in temperature. The basic principle is that heat moves from areas of higher temperature to areas of lower temperature.

2. **Temperature Difference**: When you have two objects, one hot and one cold, the heat will continue to flow from the hot object to the cold object as long as there is a temperature difference between them.

3. **Equalization of Temperature**: The flow of heat will continue until the temperatures of both objects become equal. This means that the hot object will lose heat and cool down, while the cold object will gain heat and warm up.

4. **Stopping of Heat Flow**: Once the temperatures of both objects are equal, there is no longer a temperature difference. At this point, the flow of heat stops because heat transfer requires a temperature gradient.

5. **Conclusion**: Therefore, the flow of heat from a hot object to a cold object stops when the temperature of both objects becomes equal.

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