Question

two identical blocks are heated to different temperatures. the blocks are placed so that they touch, and heat begins to flow between the blocks. the pair of blocks is insulated, so no energy escapes. later, the temperature of each block is measured again. which pair of temperatures is possible?

Explanation:

Step1: Understand heat - flow principle

Heat flows from a hotter object to a colder object until thermal equilibrium is reached. The initial temperatures are 112°C for Block 1 and 92°C for Block 2. The final temperatures of the two - block system (since they are insulated) should be such that the temperature of the hotter block decreases and the temperature of the colder block increases.

Step2: Analyze each option

• Option 1: Block 1 is 105°C and Block 2 is 99°C. Block 1 has cooled down from 112°C and Block 2 has heated up from 92°C, which is consistent with heat - flow.
• Option 2: Block 1 is 99°C and Block 2 is 105°C. This is incorrect because heat should flow from the initially hotter Block 1 to Block 2, so Block 1 should not end up at a lower temperature than Block 2.
• Option 3: Block 1 is 112°C and Block 2 is 109°C. Block 1 has not cooled down, which is incorrect as heat must flow from it to Block 2.
• Option 4: Block 1 is 102°C and Block 2 is 82°C. Block 2 has cooled down further, which is incorrect as it should gain heat from Block 1.

Answer:

Block 1: 105°C, Block 2: 99°C