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AP EAMCET · PHYSICS · Dual Nature of Matter

Light of wavelength \(4000 Å\) is incident on a sodium surface for which the threshold wavelength of photo electrons is \(5420 Å\). The work function of sodium is

  1. A 4.58 eV
  2. B 2.29 eV
  3. C 1.14 eV
  4. D 0.57 eV
Verified Solution

Answer & Solution

Correct Answer

(B) 2.29 eV

Step-by-step Solution

Detailed explanation

\(\lambda = 4000 Å, \lambda_0=5420 Å\) \(\therefore\) Work function, \(\begin{aligned} \phi_0=\frac{12400}{\lambda_0(\mathrm{in} Å)} \mathrm{eV} & =\frac{12400}{5420} \\ & =2.29 \mathrm{eV}\end{aligned}\)