JEE MAIN - Physics (2024 - 30th January Morning Shift - No. 2)
The work function of a substance is $$3.0 \mathrm{~eV}$$. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately;
215 nm
400 nm
414 nm
200 nm
Explanation
$$\begin{aligned}
& \text { For P.E.E. : } \lambda \leq \frac{h c}{W_e} \\
& \lambda \leq \frac{1240 \mathrm{~nm}-\mathrm{eV}}{3 \mathrm{eV}} \\
& \lambda \leq 413.33 \mathrm{~nm} \\
& \lambda_{\max } \approx 414 \mathrm{~nm} \text { for P.E.E. }
\end{aligned}$$
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