Concepts Of Physics MCQ Edition [Volume 2]PhysicsCalorimetry
Upon mixing a hot liquid with a cold liquid, the temperature of the mixture
Options
- Aincreases initially, then becomes constant
- Bincreases continuously
- Cremains undefined for some time before becoming nearly constant
- Ddecreases initially, then becomes constant
Correct answer
C. remains undefined for some time before becoming nearly constant
Step-by-step solution
Temperature is a macroscopic property that is defined only when a system is in thermal equilibrium. When a hot liquid is mixed with a cold liquid, the system is initially not in thermal equilibrium, as different parts of the mixture are at different temperatures. Therefore, the temperature of the mixture as a whole remains undefined during this transient state. After some time, heat exchange takes place between the hot and cold liquids until thermal equilibrium is established. At this point, the temperature of the