Question 40 A vertical air current that is generated by temperature-induced density differences is an example of heat transfer by transmission convection conduction advection

To determine the correct answer, let's analyze the options provided in the context of heat transfer mechanisms: 1. **Transmission**: This term generally refers to the transfer of energy through a medium, often associated with electromagnetic waves. It is not typically used to describe heat transfer in fluids. 2. **Convection**: This is the process of heat transfer through a fluid (liquid or gas) caused by the movement of the fluid itself. In this case, the vertical air current generated by temperature-induced density differences is a classic example of convection, as warmer, less dense air rises while cooler, denser air sinks. 3. **Conduction**: This is the transfer of heat through a solid material without the movement of the material itself. It occurs through direct contact between molecules and is not applicable to the scenario described. 4. **Advection**: This term refers to the horizontal transfer of heat or other properties in a fluid. While it involves fluid movement, it is not specifically about vertical currents caused by temperature differences. Given this analysis, the correct answer is: **Convection**.