The nature of light has been a subject of scientific inquiry for centuries, and our understanding of it has evolved over time. Light exhibits both particle-like and wave-like properties, which is one of the fundamental aspects of quantum mechanics.
In the context of quantum physics, light can be described as both particles called photons and as electromagnetic waves. The wave-particle duality suggests that light can exhibit properties of both waves and particles, depending on how it is observed or measured.
When considering light as a particle, such as a photon, it is true that photons are considered to be massless. According to Einstein's theory of relativity, the mass of an object increases as its velocity approaches the speed of light. Since light travels at the speed of light, its mass would theoretically become infinite if it had any mass to begin with. Experimental evidence supports the notion that photons are massless.
However, despite being massless, photons do possess energy and momentum. The momentum of a photon is related to its wavelength or frequency through the equation p = h/λ, where p represents momentum, λ represents wavelength, and h is Planck's constant. This relationship implies that photons can transfer momentum when they interact with matter, such as when they are absorbed or reflected.
Regarding the concept of light as an energy wave, it is important to note that light is composed of oscillating electric and magnetic fields. These fields propagate through space as electromagnetic waves, and their interactions give rise to various phenomena such as diffraction, interference, and polarization. The energy of light is carried by these waves, and the intensity or brightness of light is related to the energy transported by the waves.
In summary, while photons are massless particles, they possess momentum and energy. Light can be described as both particles (photons) and electromagnetic waves, exhibiting wave-particle duality. The energy of light is associated with the oscillating electric and magnetic fields that propagate as electromagnetic waves through space.