Concepts Of Physics MCQ Edition [Volume 2]PhysicsCalorimetry
Two bodies at unequal temperatures are mixed inside a calorimeter. Which of the following quantities remains conserved?
Options
- AThe sum of the temperatures of the two bodies
- BThe internal energy of each individual body
- CThe total internal energy of the two bodies
- DThe total heat of the two bodies
Correct answer
C. The total internal energy of the two bodies
Step-by-step solution
A calorimeter acts as an isolated system where no heat exchange takes place with the surroundings. According to the first law of thermodynamics, Q = U + W . Since the system is isolated, the net heat exchange with the surroundings is zero ( Q = 0 ) and no external work is done ( W = 0 ). Therefore, the change in the total internal energy of the system is zero ( U = 0 ). This implies that the total internal energy of the two bodies remains conserved during the mixing process, even though heat flows from the hotter b