The difference between threshold wavelengths for two metal surfaces A and B having work function ϕ A =…

The difference between threshold wavelengths for two metal surfaces A and B having work function ϕA=9eV and ϕB=4.5eV in nm is:

{Given, hc=1242 eV nm}

  1. 540
  2. 276
  3. 264
  4. 138

Solution

The work function is given by 

hcλ=ϕ

⇒λ=hcϕ

By the given data,

λA=12429 nm, λB=12424.5 nm, 

The difference between the wavelengths,

λB-λA=12424.5-12429 nm=12429 nm

=138 nm

Asked in: JEE Main 2023 (13 Apr Shift 1)

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