JEE MainPhysicsDual Nature of Matter
A metal surface is illuminated by various colors of light. It is observed that green light of wavelength 500 nm causes photoelectric emission, but yellow light of wavelength 580 nm does not. Which of the following could be the possible value of the work function of the metal? (Take hc = 1240 eV nm )
Options
- A1.9 eV
- B2.7 eV
- C4.62 eV
- D2.3 eV
Correct answer
D. 2.3 eV
Step-by-step solution
The energy of an incident photon is given by E = hc . For green light ( = 500 nm ): E_G = 1240 500 = 2.48 eV For yellow light ( = 580 nm ): E_Y = 1240 580 2.14 eV Since green light causes emission, the work function must be less than the energy of the green light photons: Since yellow light does not cause emission, the work function must be greater than the energy of the yellow light photons: > 2.14 eV . Thus, the work function must lie in the range 2.14 eV Among the given options, only 2.3 eV falls within this ran