In Einstein's photoelectric explanation, what is the fundamental inter…

Question

In Einstein's photoelectric explanation, what is the fundamental interaction between light and a metal electron?

Accepted Answer

B. One photon transfers all its energy to one electron in a single, instantaneous event

1. Einstein's 1905 quantum hypothesis (NCERT §11.6) is that light energy is delivered in discrete packets called photons.
2. The photoelectric interaction is ONE photon to ONE electron, and the energy transfer is INSTANTANEOUS.
3. The ejected electron receives the photon's energy $h
u$. Part of it $\phi_0$ goes into escaping the metal, the rest becomes kinetic energy: $K_{\max} = h
u - \phi_0$.
4. Option A is the classical wave picture (which fails — it predicts a build-up time before emission, observed to be < $10^{-9}\,	ext{s}$). Option C contradicts the experimental fact that intensity (more photons) raises current, not energy per electron. Option D is the thermionic emission picture, not photoelectric.
_Source: NCERT Class 12 Physics Part 2, Ch 11, §11.6 (Einstein's photoelectric equation), p. 7._

Answer

Many photons combine their energies and collectively eject one electron

Answer

Each photon ejects multiple electrons as long as it has enough energy

Answer

Photons heat the metal first; thermal electrons then escape continuously