Photoelectric effect is explained if light is considered to travel in the form of

Explanation

The photoelectric effect is a phenomenon where electrons are emitted from a material when it is exposed to light. This effect can only be explained if light is considered to travel in the form of particles, or photons. Each photon carries a quantized amount of energy, and when it strikes the surface of a material, it transfers this energy to an electron. If the energy is sufficient, the electron is ejected from the material. This particle nature of light aligns with the observations of the photoelectric effect, where increasing the frequency of light increases the energy of the emitted electrons, not the intensity of the light. Option A, 'Waves', is incorrect because the wave model cannot account for the threshold frequency needed to emit electrons or the independence of electron energy from light intensity. Option C, 'Both waves and particles', is misleading in this context because, although light exhibits wave-particle duality, the photoelectric effect specifically requires a particle explanation. Option D, 'None of these', is incorrect because the particle model (Option B) correctly explains the phenomenon.