Concepts Of Physics MCQ Edition [Volume 2]PhysicsBohr's Model and Physics of the Atom
Radiation emitted from a hydrogen discharge tube is incident on a cesium plate. Determine the maximum possible kinetic energy of the emitted photoelectrons. The work function of cesium is 1.9 eV .
Options
- A15.5 eV
- B8.3 eV
- C11.7 eV
- D1.5 eV
Correct answer
C. 11.7 eV
Step-by-step solution
The maximum energy of a photon emitted from a hydrogen discharge tube corresponds to the transition of an electron from n = to n = 1 . The energy of this incident photon is: E = 13.6 ( 1 1^2 - 1 ^2 ) = 13.6 eV According to Einstein's photoelectric equation, the maximum kinetic energy of the emitted photoelectrons is: K_ max = E - Substituting the given work function of cesium = 1.9 eV : K_ max = 13.6 - 1.9 = 11.7 eV