The question asks for the experiment that provided direct evidence for the particle nature of light. We need to recall the fundamental experiments in quantum physics and their implications regarding the wave-particle duality of light and matter.
Correct Option: C) Photoelectric effect experiment. This experiment, explained by Einstein, provided conclusive evidence that light behaves as particles (photons) when interacting with matter, directly supporting the particle nature of light.
The question asks to identify the phenomenon that provides evidence for the wave nature of light. We need to evaluate each option based on whether it supports the wave theory or the particle (quantum) theory of light.
C) Diffraction — Diffraction is the bending and spreading of light waves as they pass through an aperture or around an obstacle. The characteristic interference patterns observed during diffraction (e.g., bright and dark fringes) are a direct consequence of the wave nature of light, where different parts of the wavefront interfere with each other. This phenomenon cannot be explained by treating light purely as particles.
The question asks to identify the scientist credited with the theory of wave-particle duality. We need to recall the major contributions of each scientist listed in the options to determine who proposed this fundamental concept in quantum mechanics.
C) Louis de Broglie is credited with the theory of wave-particle duality. He proposed that all matter exhibits wave-like properties, a concept that was later experimentally confirmed.
The question asks to identify the phenomenon that demonstrates the wave nature of particles. We need to evaluate each option based on its underlying physical principle.
D) Electron diffraction
Electron diffraction is the phenomenon where electrons (which are particles) exhibit wave-like properties, such as interference and diffraction, when they pass through a crystal lattice or a small aperture. This was experimentally confirmed by Davisson and Germer, and G.P. Thomson, providing direct evidence for de Broglie's hypothesis and the wave nature of particles.
The question asks about de Broglie's hypothesis, which relates the wave nature of particles to their momentum. We need to recall the de Broglie wavelength formula and identify the proportionality.
Correct Option: B) Its mass
As derived from de Broglie's equation \(\lambda = \frac{h}{mv}\), the wavelength \(\lambda\) is inversely proportional to the mass \(m\) of the particle (assuming velocity is constant). It is also inversely proportional to its velocity \(v\) (assuming mass is constant).
The photoelectric effect is a phenomenon where electrons are emitted from a material when light shines on it. Understanding the key observations and their implications is crucial for determining what aspect of light it demonstrates.
B) Has a particle nature — The photoelectric effect provides conclusive evidence that light, in its interaction with matter (like ejecting electrons), behaves as discrete packets of energy called photons, thus demonstrating its particle nature. This phenomenon was instrumental in the development of quantum mechanics.