Question

When does light behave as a wave ? When does light behave as a particle?

Answer 1

Einstein was the first to explain what was happening. He theorized that electromagnetic energy comes in packets, or quanta which we now call photons. So light behaves as a wave and as a particle, depending on the circumstances and the effect being observed. This concept is now known as wave-particle duality.

Answer 2

Explanation:

Light behaves as a wave - it undergoes reflection, refraction, and diffraction just like any wave would. Yet there is still more reason to believe in the wavelike nature of light. Continue with Lesson 1 to learn about more behaviors that could never be explained by a strictly particle-view of light.

Einstein was the first to explain what was happening. He theorized that electromagnetic energy comes in packets, or quanta which we now call photons. So light behaves as a wave and as a particle, depending on the circumstances and the effect being observed. This concept is now known as wave-particle duality.