What is Rayleigh scattering?

Rayleigh scattering is specifically caused by particles that are much smaller than the wavelength of the light being scattered. This phenomenon occurs in the atmosphere when light interacts with molecules such as nitrogen and oxygen, which have dimensions significantly smaller than the wavelengths of visible light. The effectiveness of Rayleigh scattering is inversely proportional to the fourth power of the wavelength, meaning shorter wavelengths (like blue light) scatter more than longer wavelengths (like red light). This is why the sky appears blue during the day; the shorter blue wavelengths scatter more while traveling through the atmosphere.

The other options refer to different scattering mechanisms. Option A generally describes scattering involving larger particles, which is unrelated to Rayleigh scattering. Option B suggests scattering caused by particles that are larger than the wavelength, corresponding to different scattering rules, such as Mie scattering. Option D notes scattering without energy absorption, though Rayleigh scattering inherently involves a transfer of energy and does not fit this description accurately. Understanding these distinctions helps clarify Rayleigh scattering's unique role in atmospheric optics.