Red Seal Plumbing Practice Exam

What causes a slight increase in gas temperature as it moves along the pipe?

1. Condensation

2. Expansion

3. Friction

4. Radiation

The correct answer is: Friction

The other options, including condensation, expansion, and radiation, do not accurately describe the cause of a slight increase in gas temperature as it moves along the pipe. Condensation occurs when gas turns into a liquid due to a decrease in temperature, while expansion occurs when gas volume increases. Radiation is the transfer of heat through electromagnetic waves, which may not necessarily result in an increase in temperature. Instead, friction is the most likely cause of a slight increase in gas temperature as it moves along the pipe. When gas molecules rub against the walls of the pipe, they create friction, which produces heat and accounts for the temperature change. Therefore, option C is the correct answer.