High School

Consider the following scenario:

Our sample starts at room temperature (300 K). We place our sample in the oven set to 500 K. We then let our sample cool back to room temperature.

What is our [tex]\(\Delta T\)[/tex]?

A. 200 K
B. 0 K
C. 200 K
D. None of the other answers.

Answer :

To solve the problem of determining the total change in temperature of the sample, we can follow these steps:

1. Understand the initial and final conditions:
- The sample starts at room temperature, which is 300 K.
- It is then heated to an oven temperature of 500 K.
- After that, it cools back down to room temperature, which is again 300 K.

2. Calculate the temperature change during the heating process:
- The sample is initially at 300 K and is heated to 500 K.
- The change in temperature during the heating phase is:
[tex]\[
\Delta T_{\text{heating}} = 500\,\text{K} - 300\,\text{K} = 200\,\text{K}
\][/tex]

3. Calculate the temperature change during the cooling process:
- The sample cools from 500 K back down to 300 K.
- The change in temperature during the cooling phase is:
[tex]\[
\Delta T_{\text{cooling}} = 300\,\text{K} - 500\,\text{K} = -200\,\text{K}
\][/tex]
- Note that the cooling results in a negative change because the temperature decreases.

4. Determine the total change in temperature (absolute change):
- To find the total change in temperature, consider the absolute change during both processes:
[tex]\[
\text{Total change} = \Delta T_{\text{heating}} + |\Delta T_{\text{cooling}}|
\][/tex]
- Substitute the values we calculated:
[tex]\[
\text{Total change} = 200\,\text{K} + 200\,\text{K} = 400\,\text{K}
\][/tex]

Therefore, the total change in temperature ([tex]\( \Delta T \)[/tex]) for the entire process of heating and cooling is 400 K.