Concepts Of Physics MCQ Edition [Volume 2]PhysicsPhotoelectric Effect and Wave–Particle Duality
During a photoelectric experiment, the collector plate is maintained at 2.0 V relative to a copper emitter plate ( = 4.5 eV ). A monochromatic light source of wavelength 200 nm illuminates the emitter. Determine the minimum and maximum kinetic energy of the photoelectrons upon reaching the collector.
Options
- A2.0 eV and 8.2 eV
- B4.5 eV and 6.2 eV
- C0 eV and 1.7 eV
- D2.0 eV and 3.7 eV
Correct answer
D. 2.0 eV and 3.7 eV
Step-by-step solution
The energy of the incident photon is given by: E = hc = 1240 eV nm 200 nm = 6.2 eV According to Einstein's photoelectric equation, the maximum kinetic energy of the emitted photoelectrons is: K_ = E - = 6.2 eV - 4.5 eV = 1.7 eV The minimum kinetic energy of the emitted photoelectrons is: K_ = 0 eV The collector plate is maintained at a positive potential of 2.0 V relative to the emitter. Therefore, the electrons are accelerated and gain an additional kinetic energy of 2.0 eV . The maximum kinetic energy of the phot