Light behaves as which of the following when traveling through a vacuum?

Light behaves as both a wave and a particle when traveling through a vacuum, a concept known as wave-particle duality. This duality is fundamental to quantum mechanics.

When considering light as a wave, it exhibits properties such as interference and diffraction, which are characteristic behaviors of waves. These phenomena can be observed in experiments like the double-slit experiment, where light creates an interference pattern, suggesting it propagates as a wave.

On the other hand, light also behaves as a particle through the concept of photons. Photons are discrete packets of energy that light can be understood to consist of, especially when considering interactions with matter, such as the photoelectric effect, where light ejects electrons from a material. This particle aspect of light highlights how photons carry energy and momentum.

Understanding light's dual nature is crucial for comprehending various phenomena in physics and optics, making it a key aspect of the study of electromagnetic radiation and quantum theory.