Final answer:
The intensity of solar radiation decreases more quickly for ultraviolet light due to its higher energy, which is readily absorbed by atoms and molecules. In contrast, infrared light has a gentler drop-off in intensity because it has longer wavelengths and lower energy. Planck's theory on quantized emission further explains why this drop-off occurs more steeply for UV light.
Step-by-step explanation:
The intensity of solar radiation drops off more rapidly for shorter wavelength ultraviolet (UV) light compared to longer wavelength infrared (IR) light. This is due to the higher energy associated with shorter wavelengths, which makes UV light capable of causing more damage to living cells and materials upon absorption.
This phenomenon is related to the concept of blackbody radiation, where the distribution of light emitted by a body, such as the Sun, depends on its temperature. The Sun emits a spectrum of light that peaks in the visible region, but due to energy considerations and Max Planck's quantum hypothesis, the emission lessens sharply as the wavelength decreases beyond the visible spectrum.
In the early 20th century, Max Planck addressed the ultraviolet catastrophe, proposing that the probability of light being emitted at shorter wavelengths was reduced due to quantization, causing the radiance curve from a blackbody to fall off at higher frequencies instead of rising infinitely as classical theory suggested. This factor is also temperature-dependent, affecting the overall distribution of solar radiation across different wavelengths.
Furthermore, the solar spectrum is more intense in the red part of the visible light spectrum compared to the violet end. Red light has the lowest frequencies and longest wavelengths, while violet light has the highest frequencies and shortest wavelengths, contributing to the Sun's yellowish appearance.