What band of solar radiation is characterized mainly by its thermal effect?

Infrared radiation is primarily associated with thermal effects due to its wavelengths being longer than visible light. This portion of the electromagnetic spectrum is responsible for transferring heat, and when it interacts with an object, it can cause the object to warm up. Infrared rays are emitted by all objects based on their temperature; thus, humans and other warm bodies emit infrared radiation, making it essential in applications such as thermal imaging and heat detection.

Other options do not primarily indicate thermal effects. Ultraviolet radiation, for instance, is known for its effects on biological organisms, including skin damage and vitamin D synthesis. Ultrablue, which typically refers to a segment of the blue visible light spectrum, does not have significant thermal characteristics. Infraviolet is not a standard classification within the electromagnetic spectrum, and it's less recognized compared to the established terms. Hence, infrared is clearly distinguished as the band characterized mainly by its thermal impact.