JEE Main 2025 — Dual Nature of Matter Question with Solution
JEE Main 2025 (22 Jan Shift 2)
Question
A light source of wavelength illuminates a metal surface and electrons are ejected with maximum kinetic energy of 2 eV . If the same surface is illuminated by a light source of wavelength , then the maximum kinetic energy of ejected electrons will be (The work function of metal is 1 eV )
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Show full solutionCorrect option: D
Correct answer
D5 eV
Step-by-step explanation
Einstein's photoelectric equation
$\begin{aligned}
& \mathrm{KE}=\frac{h c}{\lambda}=\phi_0 \\
& 2 \mathrm{eV}=\frac{h c}{\lambda}-1 \mathrm{eV} \\
& \frac{h c}{\lambda}=3 \mathrm{eV} \\
& \mathrm{KE}^{\prime}=\frac{h c}{(\lambda / 2)}-\phi_0=6 \mathrm{eV}-1 \mathrm{eV}
\end{aligned}$
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