By which method does the sun heat the troposphere?
A. Radiation
B. Conduction
C. Convection
D. Condensation
From Google:
The sun emits a vast amount of energy, which travels across space in the form of short-wave radiation. Only a tiny portion of this power actually reaches the surface. But most of the atmosphere isn't directly heated by solar radiation, but rather by the terrestrial radiation that the planet itself emits.
The sun heats the troposphere primarily through the process of radiation. To understand why radiation is the correct answer, it is important to know the definitions and characteristics of the other options as well.
Conduction is the transfer of heat energy through direct contact between two objects. In the case of the sun and the troposphere, there is no direct contact for heat transfer to occur. The vast distance between the sun and the Earth prevents any substantial conduction of heat.
Convection, on the other hand, refers to the transfer of heat through the movement of a fluid (liquid or gas). While convection does play a role in the movement of warm air within the troposphere, it does not directly heat the troposphere from the sun. Convection occurs as warm air rises, expands, and then cools before sinking back down.
Condensation is the process in which water vapor in the atmosphere changes into liquid water. It is a result of cooling air, but it is not directly involved in heating the troposphere.
Radiation is the transfer of heat through electromagnetic waves. In the case of the sun and the troposphere, the sun emits solar radiation in the form of electromagnetic waves, particularly in the visible and infrared spectrum. When these electromagnetic waves reach the Earth's atmosphere, they are absorbed by the molecules and particles in the troposphere. As a result, the energy of the radiation is converted into heat, thus heating the troposphere.
Therefore, the correct answer is A. Radiation.