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CUET · PHYSICS · PYQ PAPER 2023

In hydrogen atom light corresponding to the transition \(n=4\) to \(n=2\) falls on cesium metal. The work function of the metal is 1.9 eV . What is the maximum kinetic energy of the photoelectrons emitted?

  1. A 0.65 eV
  2. B -4.45 eV
  3. C -0.65 eV
  4. D 4.45 eV
Verified Solution

Answer & Solution

Correct Answer

(A) 0.65 eV

Step-by-step Solution

Detailed explanation

\(E = 13.6 \text{ eV} \left( \frac{1}{2^2} - \frac{1}{4^2} \right) = 13.6 \text{ eV} \left( \frac{1}{4} - \frac{1}{16} \right) = 13.6 \text{ eV} \left( \frac{3}{16} \right) = 2.55 \text{ eV}\) \(KE_{max} = E - \phi = 2.55 \text{ eV} - 1.9 \text{ eV} = 0.65 \text{ eV}\)