Q 12-11-010NEETNEET 2023Top questionEasy
The work functions of Caesium (Cs), Potassium (K) and Sodium (Na) are $2.14$ eV, $2.30$ eV and $2.75$ eV respectively. If incident electromagnetic radiation has an incident energy of $2.20$ eV, which of these photosensitive surfaces may emit photoelectrons?
Answer: (A) Cs only
Photoelectrons are emitted only if the photon energy is greater than the work function.
$2.20\ \text{eV} > 2.14\ \text{eV}$ (Cs), but $2.20\ \text{eV} < 2.30\ \text{eV}$ (K) and $< 2.75\ \text{eV}$ (Na).
Only caesium emits.
Solution by Sreeraj P, M.Sc Physics