The photoelectric effect experiment, conducted by Albert Einstein in 1905, provided significant insights into the nature of light. It revealed that light can behave as discrete particles called photons, rather than just waves. This revolutionary finding helped in understanding various phenomena in physics and laid the groundwork for the development of quantum mechanics.

To grasp the particle nature of light, let's consider a simple analogy with a basketball game. Imagine you are sitting courtside, observing the game. You realize that players can be described as both particles and waves. When a player shoots the basketball, it behaves like a particle, traveling in a straight line towards the hoop. However, when two players collide or pass the ball to each other, you notice wave-like interference patterns. This duality of behavior is similar to what occurs with light.

In the case of photons, these particles carry specific amounts of energy, known as quanta. The energy of each photon is directly proportional to its frequency according to the equation E = hf, where E is the energy, h is Planck's constant (approximately 6.626 × 10^-34 J.s), and f is the frequency of the light.

This phenomenon has profound implications. For instance, with the photoelectric effect experiment, it was observed that the kinetic energy of ejected electrons depends on the frequency, and not the intensity, of incident light. If the frequency is below a certain threshold, no electrons are emitted, regardless of high intensity. This behavior contradicted classical wave theory, but was readily explained through the particle nature of light.