A monochromatic neon lamp with wavelength of 670 . 5   nm illuminates a photo-sensitive material which…

A monochromatic neon lamp with wavelength of 670.5 nm illuminates a photo-sensitive material which has a stopping voltage of 0.48 V. What will be the stopping voltage if the source light is changed with another source of wavelength of 474.6 nm ?
  1. 0.24 V
  2. 1.5 V
  3. 1.25 V
  4. 0.96 V

Solution

eVs=hcλ-ϕ

eV'-V=hc1λ'-1λ

V'=hce1λ'-1λ+V

=12401474-1670+0.48=1.25eV

Asked in: JEE Main 2021 (27 Aug Shift 2)

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