According to Christiaan Huygens, what is light made up of?

• A. Atoms
• B. Particles
• C. Waves
• D. Electrons

Answer: (C)

Christiaan Huygens proposed the wave theory of light, which was a significant development in the understanding of light's behavior. According to Huygens, light can be described as waves that propagate through a medium. His wave theory explained phenomena such as reflection and refraction, demonstrating that light travels in wavefronts.

The key takeaway from Huygens' perspective is that light behaves like a wave, capable of interference, diffraction, and other wave-like properties. This idea laid the groundwork for the later developments in wave optics and was instrumental in shaping modern physics' understanding of light.

In contrast, the other options—atoms, particles, and electrons—refer to different concepts that do not align with Huygens' wave theory. While particles were later a part of the photon concept in quantum mechanics, Huygens specifically focused on the wave nature of light.