JEE Mains · Physics · STD 12 - Dual nature of radiation and matter
- JEE Mains 2026
- Medium
- MCQ
A light wave described by \(E =60 \sin \left(3 \times 10^{15}\right) t + \sin \left(12 \times 10^{15}\right)\) t] (in SI units) falls on a metal surface of work function 2.8 eV . The maximum kinetic energy of ejected photoelectron is (approximately) _________ eV .
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) 5.1
Step-by-step Solution
Detailed explanation
\(\omega_1=3 \times 10^{15} rad / sec\)
\(\omega_2=12 \times 10^{15} rad / sec\)
\(\because \quad v=\frac{\omega}{2 \pi}\)
\(E_{\text {photon }}=h v=6.6 \times 10^{-34} \times 1.91 \times 10^{15}\)
\(=1.26 \times 10^{-18} J\)
\(E _{\max }=\frac{1.26 \times 10^{-18}}{1.6 \times 10^{-19}} \simeq 7.9 eV\)
\(K _{\max }= E _{\max }-\phi_0\)
\(=7.9-2.8\)
\(K _{\max }=5.1 eV\)
\(\omega_2=12 \times 10^{15} rad / sec\)
\(\because \quad v=\frac{\omega}{2 \pi}\)
\(E_{\text {photon }}=h v=6.6 \times 10^{-34} \times 1.91 \times 10^{15}\)
\(=1.26 \times 10^{-18} J\)
\(E _{\max }=\frac{1.26 \times 10^{-18}}{1.6 \times 10^{-19}} \simeq 7.9 eV\)
\(K _{\max }= E _{\max }-\phi_0\)
\(=7.9-2.8\)
\(K _{\max }=5.1 eV\)
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