Quantum mechanics tells us that light can behave simultaneously as a particle or a wave. However, there has never been an experiment able to capture both natures of light at the same time; the closest we have come is seeing either wave or particle, but always at different times.

The de Broglie hypothesis states that particles of matter can behave as both waves and particles, just like light.

Photoelectric effect

The light particle conceived by Einstein is called a photon. The main point of his light quantum theory is the idea that light’s energy is related to its oscillation frequency (known as frequency in the case of radio waves). Oscillation frequency is equal to the speed of light divided by its wavelength.

The energy of the electron is deposited at a point, just as if it was a particle. So while the electron propagates through space like a wave, it interacts at a point like a particle. This is known as wave-particle duality.

The Wave-Particle Duality theory states that waves can exhibit particle-like properties while particles can exhibit wave-like properties. This definition opposes classical mechanics or Newtonian Physics.

physicist Albert Einstein

Wave–particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. For macroscopic particles, because of their extremely short wavelengths, wave properties usually cannot be detected.

The difference between the particle and waves are: The particle is defined as the small quantity of matter under the consideration. The wave is defined as the propagating dynamic distrubance. The energy of the wave is calculated based on the wavelength and velocity.

At the speed of light, both photons pass. Photons are bosons, considered by the subatomic particles, with no electric charge or resting mass and one unit of spin; they are field particles that are assumed to be electromagnetic field carriers.

The photon belongs to the class of bosons. Like all elementary particles, photons are currently best explained by quantum mechanics and exhibit wave–particle duality, their behavior featuring properties of both waves and particles.

Answer 2: No, in fact light only stops when it is absorbed by an electron in an atom of an object. Light in a perfect vacuum travels on at its full speed until it hits something.

Science: Can photons travel ‘faster than light’? LIGHT cannot travel faster than it does in a vacuum. This, at any rate, is what Einstein postulated in 1905. The proposed effect, however, is very small indeed: the photons can exceed Einstein’s limit by only one part in 1036.

A photon of light does not accelerate to light speed. It’s not like a photon jumps from a speed of zero to light speed instantaneously. Rather, a photon is always traveling at c, from the moment of its creation.

When an electron is hit by a photon of light, it absorbs the quanta of energy the photon was carrying and moves to a higher energy state. Electrons therefore have to jump around within the atom as they either gain or lose energy. …

They worked out that – very rarely – two particles of light, or photons, could combine to produce an electron and its antimatter equivalent, a positron. Electrons are particles of matter that form the outer shells of atoms in the everyday objects around us.

the size of photons and electrons are same as mass,but electron is negatively charged particle and photon is the energy (quanta).