For photoelectric emission, tungsten requires light of 2300 ∘A. If light of 1800 ∘A wavelength is incident then emission
Don’t take place
May or may not take place
Depends on frequency
In tungsten, photoemission take place with a light of wavelength 2300 ∘A. As emission of electron is inversely proportional to wavelength, all the wavelengths smaller then 2300 ∘A will cause emission of electrons.