Dual Nature of Radiation and Matter - Result Question 35
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37. Light of two different frequencies whose photons have energies $1 eV$ and $2.5 eV$ respectively illuminate a metallic surface whose work function is $0.5 eV$ successively. Ratio of maximum speeds of emitted electrons will be
======= ####37. Light of two different frequencies whose photons have energies $1 eV$ and $2.5 eV$ respectively illuminate a metallic surface whose work function is $0.5 eV$ successively. Ratio of maximum speeds of emitted electrons will be
3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/dual-nature-of-radiation-and-matter/dual-nature-of-radiation-and-matter—result-question-35.md (a) $1: 4$
(b) $1: 2$
(c) $1: 1$
(d) $1: 5$
[2011]
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Answer:
Correct Answer: 37. (b)
Solution:
- (b) The maximum kinetic energy of emitted electrons is given by
$K . E=\phi-\phi_0$
$K . E_1=1 eV-0.5 eV=0.5 eV$
$K . E_2=2.5 eV-0.5 eV=2 eV$
$\therefore \frac{K \cdot E_1}{K \cdot E_2}=\frac{0.5 eV}{2 eV}=\frac{1}{4}$
$\Rightarrow \frac{v_1}{v_2}=\sqrt{\frac{1}{4}}=\frac{1}{2}$
