λhc=λ0hc+21mv2
λ0hc=λhc−21mv2
=4000×10−106.626×10−34×3×108−21(9.1×10−31)×(6×105)2
=46.626×3×10−19−29.1×6×6×10−21
=4.97×10−19−1.64×10−19
=3.33×10−19 Joule
Work function (λ0hc)=1.6×10−193.33×10−19=2.08≈2.1eV
What is the work function of the metal if the light of wavelength 4000overseto A generates photoelectrons of velocity 6× 10^5 ms^-1 from it? (Mass of…
JEE Main 2019 — Chemistry Physical Chemistry
2019mcqeasy
What is the work function of the metal if the light of wavelength 4000Ao generates photoelectrons of velocity 6×105ms−1 from it?
(Mass of electron =9×10−31kg, velocity of light =3×108ms−1, Planck's constant =6.626×10−34Js, Charge of electron =6.626×10−34Js)
Official previous-year question
Held on 12 Jan 2019 · Verified 6 Jul 2026.
Options
- A
0.9eV
- B
4.0eV
- C
3.1eV
- D
2.1eV
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