AP EAMCET201923 Apr 2019Morning ShiftPhysicsDual Nature of MatterActual
Light of wavelength (488 ~nm ) produced by an Agron laser is used in the photoelectric effect. When light from this spectral line is incident on the cathode, the stopping potential of the photoelectrons is (0.38 ~V ). The work function of the cathode material is
Options
- A(2.16 eV )
- B(216 eV )
- C(21.6 eV )
- D(0.216 eV )
Correct answer
A. (2.16 eV )
Step-by-step solution
Given, light of wavelength, ( =488 ~nm ) and stopping potential, of photoelectrons, (V=0.38 ~V ) As, energy of photon (E= h c = 1250 488 eV ) So, (E=2.56 eV ) ( ) Maximum kinetic energy of a photo-electron ( KE _ =e V₀ ) Where, (V₀= ) stopping potential ( KE _ =e V₀=0.38 eV ) From Einstein's photoelectric equation, ( aligned & E= KE _ +W₀ & W₀=E- KE _ & =2.56-0.38=2.18 2.16 eV aligned ) Hence, the work function of cathode material is (2.16 eV ). So, the correct option is (a).