Physics · 2021
JEE Main · 25 July 2021, Shift 2 · Q18
When radiation of wavelength λ is incident on a metallic surface, the stopping potential of ejected photoelectrons is 4.8 V. If the same surface is…
When radiation of wavelength $\displaystyle \lambda$ is incident on a metallic surface, the stopping potential of ejected photoelectrons is $\displaystyle 4.8$ V. If the same surface is illuminated by radiation of double the previous wavelength, then the stopping potential becomes $\displaystyle 1.6$ V . The threshold wavelength of the metal is:
Official answer
(2)
$\displaystyle 4 \lambda$
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JEE Main 2021 Physics question, with the answer from NTA’s final answer key. Where our answers come from.