Assertion (A) : Work function of aluminum is 4.2 eV. If two photons each of energy 2.5 eV strikes on a piece of aluminum, the photo electric emission does not occur.
Reason (R) : In photo electric effect a single photon interacts with a single electron and electron is emitted only if energy of each incident photon is greater then the work function.
Answer & explanation
Correct answer: option 1
A single photon of energy more than the work function is required to emit the electron.