Answer:
(iii) Increasing the intensity of radiation would increase the number of photons hitting the surface per second. As a result, the number of electrons ejected per second would also increase, as the photoelectric effect is a stochastic process. However, the maximum kinetic energy of the ejected electrons would not change, as it depends solely on the frequency of the incident photons.
In terms of photons, increasing the intensity of radiation would mean an increase in the number of photons per unit area per second. This would increase the probability of a photon interacting with an electron and causing ejection.
(iv) Einstein's theory that light behaved as particles, or photons, was controversial in 1902 because it contradicted the established wave theory of light. Many physicists at the time believed that light waves were similar to sound waves, and that they propagated through a medium called the "luminiferous ether." Einstein's theory challenged this idea by suggesting that light was made up of discrete particles, or photons, with specific energies.
However, Einstein's theory was later supported by experiments such as the photoelectric effect, which demonstrated that light could indeed behave like particles. Furthermore, the theory of quantum mechanics developed in the early 20th century provided a more complete understanding of the dual nature of light, which can behave as both particles and waves. Today, the particle nature of light is widely accepted and is a standard concept in pre-university physics.