The amount of electromagnetic radiation emitted from an object depends on what factor?

The amount of electromagnetic radiation emitted from an object is fundamentally tied to its temperature, following principles established by Planck's law of black-body radiation. As an object's temperature increases, it emits more electromagnetic radiation, and this radiation shifts to shorter wavelengths. For example, a hot object will emit more radiation in the visible spectrum and can even glow brightly, while a cooler object emits radiation primarily in the infrared range. This relationship is critical in various fields, including thermography and astrophysics, where temperature plays a central role in understanding radiation emissions from stars and planets.

The other factors listed do not have a direct correlation with the amount of electromagnetic radiation an object emits. Height above sea level may affect atmospheric conditions but does not change the inherent electromagnetic properties of the object itself. Humidity levels can influence certain measurements and atmospheric absorption of radiation, but they do not affect the thermal radiation emitted by an object. Similarly, while the time of day can change the environmental conditions surrounding an object, it does not alter the object's intrinsic capacity to emit radiation based on temperature.