The interpretation of the two results (A red light was shined onto a metal sample and the result shown in (i) was observed. When the light source was changed to a blue light, the result shown in (ii) was observed), the expected results when the intensity of red and blue lights is increased and the expected result when violet light is used should be explained by using the concept of photoelectric effect.
Albert Einstein explained famous mysterious phenomenon, called the photoelectric effect. In the photoelectric effect, electrons are ejected from the surface of a metal when it is exposed to the light. The incident light should be of a certain minimum frequency called the threshold frequency. The number of electrons ejected was proportional to the intensity of the light. The energies of the ejected electrons weren’t related to it. Electrons weren’t ejected below the threshold frequency.
The Apparatus shown is used for studying the photoelectric effect. The incident light of a certain frequency falls on a clean metal surface. Ejected electrons are attracted toward the positive electrode. The flow of electrons is registered by a detecting meter. Einstein suggested that a beam of light is a stream of particles. These “particles” of light are called photons.