Answer:
This is explained as the wave-particle duality of light.
Step-by-step explanation:
Wave motion is said to occur when a kind of periodic disturbance is propagated through a medium, such as local electric or magnetic fields, or sound waves moving transversely through a guitar string. For each medium, there is a characteristic velocity at which the disturbance travels. The quantifiable properties of wave motion are its wavelength, amplitude and frequency. Light has similar parameters: wavelength, velocity (speed of light) and frequency - and behaves as such that it can reflect, diffract, refrract, etc, which allows it to be measured as a wave. Furthermore. visible light is a region on the electromagnetic spectrum.
Light can also be observed as a particle of discrete bundles of electromagnetic energy, known as photon. When light comes in contact with the electrons in an object or substance, the electrons get excited and moves from the surface of the material. So, if a photon of greater energy than that of an electron hits a solid that electron will be emitted.