Physics · Atomic Physics

NEET (UG) 2023 — Question 2

The work functions of Caesium (Cs), Potassium ( K ) and Sodium ( Na ) are 2.14 eV , 2.30 eV and 2.75 eV respectively. If incident electromagnetic radiation has an incident energy of 2.20 eV , which of these photosensitive surfaces may emit photoelectrons?

Option A:
Both Na and K
Option B:
K only
Option C:
Na only
Option D:
Cs only
Correct

Answer: D

Step-by-step solution

Energy of incident radiation $=2.80 \mathrm{eV}$ Work function of $\mathrm{Cs} \rightarrow 2.14 \mathrm{eV}$ Work function of $\mathrm{K} \rightarrow 2.30 \mathrm{eV}$ Work function of $\mathrm{Na} \rightarrow 2.75 \mathrm{eV}$ Since the work function of potassium and sodium are more than energy of incident radiation hence

photons may be emitted from caesium.

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Exam: NEET (UG) 2023
Paper: 2023 paper
Subject: Physics
Chapter: Atomic Physics
Topic: Photoelectric Effect

Answer: D

Step-by-step solution

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