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: Recall heat - transfer principle

Heat flows from a hotter object to a colder object until thermal equilibrium is reached. The initial temperatures are 103°C for Block 1 and 199°C for Block 2.

Step2: Analyze options

• Option 1: Block 1 at 185°C and Block 2 at 117°C has heat flowing from Block 1 to Block 2 which is incorrect as Block 2 should be the hotter one initially.
• Option 2: Block 1 at 51°C and Block 2 at 147°C has Block 1 getting colder which is incorrect as it should gain heat.
• Option 3: Block 1 at 103°C and Block 2 at 189°C means Block 1 did not gain any heat which is incorrect.
• Option 4: When thermal equilibrium is reached, the two identical blocks in an insulated system will have the same temperature. Since heat flows from the hotter (199°C) to the colder (103°C) block, they will eventually reach a common temperature between 103°C and 199°C. 151°C for both is a possible equilibrium temperature.

Answer:

The pair of temperatures where Block 1 is 151°C and Block 2 is 151°C is possible.