Final answer:
The subject of the question is the determination of pressure in a well-mixed atmosphere at a temperature of 300K assuming no condensation, which falls under the Physics category, and is appropriate for college students studying Meteorology and Atmospheric Science.
Step-by-step explanation:
The question pertains to the field of Meteorology, which is the study of the atmosphere and atmospheric phenomena with a focus on weather forecasting. In this case, the concern is about determining the pressure at which the temperature reaches 300K under the assumption that the atmosphere is well mixed and no condensation occurs.
We employ the ideal gas law, which relates pressure, volume, and temperature of an ideal gas. It is given by PV = nRT, where P is the pressure, V is the volume, n is the amount of substance, R is the ideal, or universal, gas constant, and T is the temperature in kelvin.
For a well-mixed atmosphere with no condensation, the pressure at 300K would be determined by rearranging the ideal gas law to solve for pressure, given constant volume and amount of the gas. To find a precise value for the pressure, one would need additional information, such as the volume and mole quantity of the gas.