The stopping potential for electrons emitted from a photosensitive surface illuminated by light of…

The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength 491 nm is 0.710 V. When the incident wavelength is changed to a new value, the stopping potential is 1.43 V. The new wavelength is :
  1. 382 nm
  2. 309 nm
  3. 329 nm
  4. 400 nm

Solution

hcλ=ϕ+eVs

1240491=ϕ+0.71      ...1

1240λ=ϕ+1.43      ...2

λ=382 nm

Asked in: JEE Main 2021 (25 Feb Shift 2)

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